• Journal of Digital Convergence
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• v.13 no.5
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• pp.277-288
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• 2015

This study aims to identify determinants affecting on geographic variations in the prevalence of arthritis in Korean women using data mining. Data from Korean Community Health Survey 2012 with 249 small districts were analyzed. Socio-demographic, health behavior and status, and morbidity status measures were analyzed using conventional regression model and convergence analysis method such as decision tree for convergence analysis. Rate of workers in agriculture, forestry, and fishing, salaried workers, persons higher than high school graduates, non-treatment of needing care, non-treatment of care because of economic reason, obesity, heavy drunkers, complaining persons of chewing difficulty, persons with experiencing depression, persons with perceiving stress, and persons with diagnosing hypertension and angina pectoris were variation determinants of prevalence of arthritis in 249 small districts and these districts were classified 10 area groups by decision tree model. Our finding suggest that the approach based characteristics by small area groups rather than national wide or individual level would be effective to reduce in variations of prevalence of arthritis.

• Communications of Mathematical Education
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• v.24 no.3
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• pp.563-585
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• 2010

The major goals of this study are to find the factors that enhance self-directed math learning in college math classes and to provide the students with the opportunities to check and develop their self-directed math learning attitude. For these research goals, we prepared the questionnaires that asked about their learning motivations, basic learning ability, self-discipline strategies, and self-directed learning strategies. Another purpose of the questionnaires was to give them the chances to check and improve their attitude toward those learning strategies, motivation and ability. From the research results, we find that the important factors for self-directed learning are internal & external motivations, concentration ability, and the goal-setting and plan-making abilities. In addition, concentration ability, good habit, stress-control, recognition of math value, and self-directing ability are found to be necessary for the desirable learning environment. On the other hand, we find that the ability to perform note-taking, class preparation and review, time-control, and test-control is required for the selection and practice of self-fitting learning strategies. Finally, we provided our own self-directed math learning model. Our model, containing the necessary factors for self-directed math learning, is the revised and modified one of Knowles(1975)'s 5 stage self-directed learning model that comprises diagnosis of learning desire, setting learning goals, grasping human&material resources, selection and practice of proper learning strategies, and evaluation of learning results.

• Journal of the Korean Geotechnical Society
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• v.29 no.2
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• pp.35-45
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• 2013

The void ratio is an important parameter for reflecting the soil behavior including physical property, compressibility, and relative density. The void ratio can be obtained by laboratory test with extracted soil samples. However, the specimen has a possibility to be easily disturbed due to the stress relief when extracting, vibration during transportation, and error in experimental process. Thus, the theoretical equations have been suggested for obtaing the void ratio based on the elastic wave velocities. The objective of this paper is to verify the accuracy of the proposed analytical solution through the error norm. The paper covers the theoretical methods of Wood, Gassmann and Foti. The elastic wave velocity is determined by the Field Velocity Probe in the southern part of Korean Peninsular. And the rest parameters are assumed based on the reference values. The Gassmann method shows the high reliability on determining the void ratio. The error norm is also analyzed as substitution of every parameter. The results show every equation has various characteristics. Thus, this paper may be widely applied for obtaining the void ratio according to the field condition.

• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.687-694
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• 2014

This study established a displacement ductility ratio model for ductile design for the boundary element of shear walls. To determine the curvature distribution along the member length and displacement at the free end of the member, the distributions of strains and internal forces along the shear wall section depth were idealized based on the Bernoulli's principle, strain compatibility condition, and equilibrium condition of forces. The confinement effect at the boundary element, provided by transverse reinforcement, was calculated using the stress-strain relationship of confined concrete proposed by Razvi and Saatcioglu. The curvatures corresponding to the initial yielding moment and 80% of the ultimate state after the peak strength were then conversed into displacement values based on the concept of equivalent hinge length. The derived displacement ductility ratio model was simplified by the regression approach using the comprehensive analytical data obtained from the parametric study. The proposed model is in good agreement with test results, indicating that the mean and standard deviation of the ratios between predictions and experiments are 1.05 and 0.19, respectively. Overall, the proposed model is expected to be available for determining the transverse reinforcement ratio at the boundary element for a targeted displacement ductility ratio.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1293-1299
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• 2017

Obesity contributes to the development of diseases, such as type II diabetes, hypertension, coronary heart disease, and cancer. In addition, oxidative stress caused by reactive oxygen species (ROS) is recognized widely as a contributing factor in the development of chronic diseases. This study was examined the antioxidant and anti-adipogenic activities of epigallocatechin-3-gallate (EGCG) in 3T3-L1 preadipocytes. 3T3-L1 cells were differentiated with or without EGCG for 6 days. The production of glutathione (GSH) and the activities of the antioxidant enzymes, such as glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) were measured. EGCG inhibited significantly the lipid accumulation and the expression of adipogenic specific proteins including CCAAT/enhancer binding protein ${\alpha}$ and adipocyte fatty acid binding protein. The production of intracellular ROS was decreased significantly by EGCG in 3T3-L1 cells. EGCG increased the GSH production and the activities of GPx, GR, CAT, and SOD. Moreover, EGCG increased the protein expression of glutamate-cysteine ligase and heme oxygenase-1 in 3T3-L1 cells. These results suggest that EGCG increased the activity and expression of antioxidant enzymes and suppressed the lipid accumulation in 3T3-L1 cells. Therefore, the use of phytochemicals that can maintain the GSH redox balance in adipose tissue could be promising for reducing obesity.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.318-326
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• 2002

The pathogenic marine bacterium Vibrio vulnificus is the causative agent of food-borne diseases such as life-threatening septicemia. To better understand this organism's strategies to survive osmotic stress, a mutant that was more sensitive to high osmolarity was screened from a library of mutants constructed by a random transposon mutagenesis. By a transposon-tagging method, putAP genes encoding a proline dehydrogenase and a proline permease were identified and cloned from V. vulnificus. The amino acid sequences deduced from nucleotide sequences of putAP from V. vulnificus were 38 to $59\%$ similar to those of PutA and PutP reported from other Enterobacteriaceae. Functions of putAP genes were assessed by the construction of mutants, whose putAP genes were inactivated by allelic exchanges. When proline as the sole carbon or nitrogen source was used, the putA mutant was not able to grow to the substantial level, revealing the proline dehydrogenase is the only enzyme for metabolic conversion of proline into other amino acids. Although the growth rate of the putP mutant on proline as the sole carbon or nitrogen source was significantly reduced, the mutant still grew. This indicated that at least one more proline permease is produced by V. vulnificus. The putP mutant decreased approximately $2-log_10$ CFU/ml after a hyperosmotic challenge, while the parent strain decreased approximately $l-log_10$ CFU/ml. This result suggests that the gene product of putP contributes to the osmotic tolerance of V. vulnificus.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.4
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• pp.17-23
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• 2013

The purpose of this study was to provide information on management and apply it to a roadside ground cover plant understanding the capacity of calcium chloride in the plant. The experimental group was composed of the ratio control group of calcium chloride, 0.5%, 1.0%, and 3.0% in 500g of soil. Plant materials were selected and measured according to their ecological characteristics such as ground cover plant, Pachysandra terminalis, Hosta plantaginea, Trachelospermum asiaticum, Vitex rotundifolia, Euonymus japonica and Callicarpa japonica. The acidity of the amended soil was increased gradually depending on the treatment and conductivity was continually decreased. The EX-Ca increased after the treatment, but decreased in the middle of the experiment. Pachysandra terminalis, Trachelospermum asiaticum and Euonymus japonica were able to grow and survive at the ratio of 0.5%. Hosta plantaginea and Vitex rotundifolia were able to survive at the ratio of 1.0%. Hosta plantaginea, the possible state can absorb salts due to moisture and, can be applied to ground cover plants in the roadside. The growth and development of Callicarpa japonica was poor and the leaves were open to grow for calcium chloride treatment except the control group. It was concluded that Callicarpa japonica was very sensitive to calcium chloride.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.1
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• pp.30-34
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• 2016

In this paper, we report that selective etching on N-polar face by EC (electro-chemical)-etching effect on the reduction of bowing and strain of FS (free-standing)-GaN substrates. We applied the EC-etching to concave and convex type of FS-GaN substrates. After the EC-etching for FS-GaN, nano porous structure was formed on N-polar face of concave and convex type of FS-GaN. Consequently, the bowing in the convex type of FS-GaN substrate was decreased but the bowing in the concave type of FS-GaN substrate was increased. Furthermore, the FWHM (full width at half maximum) of (1 0 2) reflection for the convex type of FS-GaN was significantly decreased from 601 to 259 arcsec. In the case, we confirmed that the EC-etching method was very effective to reduce the bowing in the convex type of FS-GaN and the compressive stress in N-polar face of convex type of FS-GaN was fully released by Raman measurement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.48-54
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• 2017

University dormitories play an important role in both the campus experience and academic achievement, as well as providing the students with their basic necessities. Further, there is a high demand to increase the capacity in order to raise the retention rate and to invite more foreign students. Students' social interaction and sense of community (SOC) also play an important role in reducing the stress associated with studying and home sickness and, consequently,the campus is a place that provides positive opportunities for their personal growth and adaptation into their peer group social culture. The purpose of this study is to investigate the effects of the physical environment of the dormitory facilities on the students' sense of community and social interaction in across-cultural background.The ${\chi}^2$ analysis indicated that individual characteristics exist regarding SOC, however, there were no statistically significant differences between the two cultural groups. The factors of SOC and physical environment were higher in the Korean student group than in the U.S. group. The regression analysis indicated that the U.S. students considered a physically comfortable environment as the primary issue for social interaction, while the Korean group placed more emphasis on a family-oriented home environment. The linear analysis confirmed that satisfaction with the physical environment influenced the social interaction and SOC level. Finally, this study suggests that creating a homely environment is more important than the functioning of the institution in university dormitory planning.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.129-133
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• 2012

To exploit plant growth promoting bacteria in the roots of Miscanthus sacchariflorus, a biomass energy crop, total 64 bacteria were isolated. For the investigation of plant growth promoting effects from the isolated bacteria, production of indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activities were tested and other cultural conditions were examined. As results, 8 isolates showed plant growth promoting effects on the M. sacchariflorus and an isolate designated Agrobacterium sp. BE516 has the highest activity by enhancing the shoot elongation over 2-fold than the control. Agrobacterium sp. BE516 produced 64 ${\mu}g$ IAA per mL and showed ACC deaminase activity which is involved in the resistance to environmental stress such as high salt and drought. It could grow at low temperature in the range from 4 to $15^{\circ}C$, at pH 4.0 and at 4% NaCl. These results indicate that the Agrobacterium sp. BE516 can be useful as a bio-fertilizer for M. sacchariflorus under the stressed conditions.