• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.452-455
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• 2008

In the present study, blow forming characteristics of commercially roiled AZ31 alloy sheets were investigated. Two different kinds of AZ31 sheets were originally fabricated by using direct casting and strip casting methods respectively. Both sheets have similar grain sizes of about $7{\mu}m$ with a relatively equiaxed structure after rolling. A series of tensile tests were carried out to get flow behavior in terms of temperature and strain rate. Also, grain size effect was investigated by annealing as-received sheet at elevated temperatures. Elongation increased with temperature increment as well expected. However, the differences in tensile test condition did not give much difference in elongation even at the temperature range where a large elongation would be expected with such as fine grain of $7{\mu}m$. Blow forming experiments showed that forming condition did not result in higher difference in dome height. However, the interesting feature from this study was that formability of this AZ31 alloy got different with stress condition. Firstly, biaxial stress condition might result in lower temperature and strain rate dependencies compared to uniaxial tension results for both DC and SC sheets. Secondly, DC showed slower grain growth in uniaxial tension than in biaxial stress state while SC has much higher grain growth rage in uniaxial tension than in bulging.

• Environmental Analysis Health and Toxicology
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• v.24 no.3
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• pp.251-259
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• 2009

This study was conducted to measure the concentration of PCBs in pine needles and soil in urban (Seoul, many artificial sources of PCBs), semi-rural (Anseong, small town located below Seoul in wind direction) and rural areas (Jincheon, rarely artificial sources of PCBs) in which the artificial production amount of PCBs are different. The total PCBs concentrations in pine needles, which did not show big difference in three sampling sites, were 107.5 pg/g (urban), 94.8 pg/g (semi-rural) and 78.8 pg/g (rural) respectively. The low chlorinated PCBs were major component in pine needles and the PCBs congener concentration profile of each sampling area were similar each other, and the octanol-air partitioning coefficient, Koa, highly correlated with the PCBs concentrations in pine needles. The total PCBs concentrations in soil which did show big difference in three sampling sites, were 830.0 pg/g (urban), 314.1 pg/g (semi-rural) and 136.5 pg/g (rural) respectively. The high chlorinated PCBs were major component in soil and the PCBs congener concentration profile of each sampling area were similar each other. There was no similarity between the PCBs concentration of pine needles and those of soil at each site, because of the different mechanism of deposition and volatilization processes of PCBs. The total PCBs concentrations of 2009 became 12.9 times lower than those of 2001. The reduce rate of PCB 28 was the greatest.

• Journal of dental hygiene science
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• v.23 no.4
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• pp.378-388
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• 2023

Background: With increasing interest in health in old age, aspects of oral aging are being considered. The Korean Academy of Geriatric Dentistry recently proposed the diagnostic criteria for oral frailty in older adults in Korea. This study aimed to conduct a cross-sectional survey of factors related to oral frailty among community-dwelling older adults and identify differences in oral frailty status according to age and sex. Methods: Among 217 older adults aged ≥60 years who visited a senior center in Wonju, 206 completed all tests for oral frailty. Among them, data from those with a Korean Version of the Modified Barthel Index score ≥90 were used in the final analysis. After evaluating oral frailty diagnostic factors such as chewing ability, occlusal force, tongue pressure, oral dryness, oral cleanliness, and swallowing function, oral hypofunction was determined according to the oral frailty diagnostic criteria. Subsequently, the evaluation results were compared based on sex and age. Results: Significant differences in chewing ability, maximum occlusal pressure, and maximum tongue pressure were observed between sexes. However, these differences did not affect oral frailty diagnosis. All diagnostic factors of oral frailty, except for the risk of oral dryness and swallowing dysfunction, showed significant differences with age. However, no significant difference was observed in the prevalence of oral frailty. Additionally, this study found no relationship between sex and oral frailty factors using the oral frailty diagnostic criteria. However, it also found that age plays a significant role as an oral frailty diagnostic indicator, in addition to oral dryness and swallowing function. Conclusion: Sex and age did not affect oral frailty diagnosis. However, patients' chewing ability, occlusal force, and tongue pressure were affected by sex and age. Therefore, sex and age should be considered when diagnosing and intervening in oral frailty in the future.

• Educational Technology International
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• v.15 no.1
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• pp.27-48
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• 2014

The purpose of the present research was to examine the relationship between the using goals of computer and self-regulated learning ability on the gender difference. To accomplish this goal, we have analyzed the data of Korea Children and Youth Panel Survey III which is nationally collected from primary school students, currently on the 6th grade in South Korea. 2,219 samples were used in the study excluding missing samples. The participants were 1167 males (49.5%) and 1052 females (50.5%). The mean age was 13.94 years (SD=.25). As results, female students spent more time on using computer than male students did: (1) the male students' time spent on Playing game was significantly larger than that of female students, but (2) on the rest seven using goals of computer including e-Learning/Information retrieval for learning, the female students spent significantly more time than the male students did. Also, in terms of the self-regulated learning ability, using computer for e-Learning/Information retrieval for learning itself gave significantly positive effects on both male and female students' self-regulated learning ability. On the other hand, Playing game gave significantly negative effects on both. Based on the results, some strategies were suggested on the proper use of computer for learning.

• Korean Journal of Community Nutrition
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• v.17 no.6
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• pp.707-713
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• 2012

The purpose of this study was to verify the difference of middle school students' eating disorder behavior and scholastic adjustment according to the gender and weight group and evaluate correlations between their eating disorder behavior and scholastic adjustment. A survey was conducted in middle school second graders attending five schools located in Seoul. Results from 355 questionnaire sheets were utilized for statistical analysis, and the results were gained as below: With regard to eating disorder behavior by gender, female students showed more eating disorder behavior than male students (p < 0.01); however, scholastic adjustment did not indicate significant differences by gender. According to the result of analyzing scholastic adjustment according to the weight group, the obese group showed lower scholastic adjustment (p < 0.05) and adjustment to studying (p < 0.01) than other groups; however, the eating disorder behavior, attachment to school, and adjustment to school did not indicate significant differences. According to the results of analyzing scholastic adjustment by eating disorder group, the normal group showed higher adjustment to studying than the risky group (p < 0.01). And scholastic adjustment, attachment to school, and adjustment to school did not indicate significant differences. The eating disorder behavior showed negative relationship with adjustment to studying. They showed more eating disorder behavior, their adjustment to studying became lower. Therefore, it is necessary to provide nutritional education at home and at school for them to have appropriate dietary habits as well as health education for them to maintain normal weight.

• Journal of Technology Innovation
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• v.31 no.3
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• pp.201-230
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• 2023

The Innovation Procurement Policy was introduced as part of the strategic public procurement policy to improve firms' innovation capabilities and enhance the public sector's ability to solve social problems by designating and purchasing so-called 'innovative products.' The pilot procurement project for innovative products was first introduced in 2019, and the policy system for designating and discovering innovative products by government departments, as well as the priority purchase system, was established in 2020. Hence, this study conducted a quantitative analysis focusing on the effectiveness of the innovation procurement system in supporting firms after it was fully implemented. For this purpose, corporate financial and employment data from 2017 to 2021 were used, and propensity score matching(PSM) and difference-in-difference(DID) methods were utilized as analytical tools. The study found that the innovation procurement system contributed to corporate growth and employment and created additional public and private sales channels. Moreover, it is necessary to enhance the innovation procurement system, such as matching innovative product-producing companies with existing SME support policies, for companies to become self-sustaining after the innovative product designation ends.

• Journal of Ginseng Research
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• v.22 no.2
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• pp.114-121
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• 1998

Osteoporosis is defined as a pathologic condition in which there occurs no change in the chemical composition of the bone, while bone resorption is abnormally increased. This compares with osteogenesis, which leads to a decrease in the amount of bone. Though many varieties of therapies have been tried, no fully effective method has been found. Korean red ginseng is an important variety of Korean ginsengs and many studies have been performed to investigate its effectiveness. But there has been no report on red ginseng's effects on osteoporosis. The purpose of this study was to determine the clinical effects of Korean red ginseng on postmenopausal osteoporosis patients. The study was designed as a double-blind study. Group I consisted of 30 postmenopausal osteoporosis patients who were administered red ginseng extracts and 15 patients who were administered maltose capsules, were included in group II. The following results were obtained after one-year administration to both groups. 1. There were no significant differences in the degree of wedging, number of compression fractures in the vertebral body, trabeculations, and Cobb's angles between the experimental and control groups. 2. Even though bone mineral density increased in the lumbar spine, and decreased in the femur, there was no significant statistical difference. 3. The serum levels of parathyroid hormone (PTH), calcium, phosphate, and alkaline phosphates showed no difference between the two groups regardless of treatment. 4. Urine Deoxy-pyridinoline (DPYD) decreased in the red ginseng group while it increased in the maltose group, but statistically there was no significant difference between the two groups. 5. The clinical presentations showed no significant differences using Visual Analog Scale. 6. The specific complications related with the long-term use of red ginseng did not occur in all patients. In conclusion, there were no statistically significant differences in clinical presentations, biochemical, and radiological studies between the red gins eng and maltose groups. No definite effectiveness of red ginseng on patients with osteoporosis was found.

• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.87-101
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• 1990

This study was undertaken to test to fit forms of the Engel curves to data. The comparisons were confined to the linear, semi-logarithmic and double-logarithmic forms. Data from the 1970-1987 Urban Household Economy Survey were used to estimate the Engel curves. The twelve categories of consumption expenditure were considered for investigation. Parameters of the Engel curves were derived from OLS and TSLS. In this paper the size of the family was used as the deflater. The results could be summarized as follows: 1. Comparing with the R2 of three foms, it could be concluded that, the linear form generally gave a better fit to data than the other forms did. Only for housing and clothing and foot wear, did the semi-logarithmic form give a better fit. Only for meals outside the home, fuel, light and water charges, and miscellaneous, did the double-logarithmic form give a better fit. 2. Comping with the income elasticities based on the alternative forms, it could be concluded that the differences between the estimates were since each form made different assumption as to the way in which elasticity varied. In general, the semi-logarithmic form gave the highest estimate and double-logarithmic form did the lowest estimate. The difference between semi-logarithmic and the other forms were greater than the those of linear and double-logarithmic form. 3. It was found that the income elasticity varied with the difinition of income used as an explanatory variable in Engel curves.

• Korean Journal of Human Ecology
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• v.12 no.3
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• pp.275-286
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• 2003

The purposes of this study were to identify the relationship between children's personality traits and self-esteem, and to find out if there were any differences in the relationship patterns in terms of children's sex. The questionnaire were collected from 984 subjects in 5th grade of elementary schools located in cities of Seoul, Suwon, Daejeon, and Daegu. Results showed that personality factors such as stability, sociability, responsibility, and superiority had stronger correlations with self-esteem factors whereas masculinity, activity level, and reflectivity did so to a less degree. Children's personality factors such as superiority, sociability and responsibility were better predictors of their self-esteem factors such as scholastic competence, social acceptance and general self-worth. Girls showed higher level of stability, sociability, responsibility and superiority, however there was no sex difference in the self-esteem such as scholastic competence, social acceptance and general self-worth. Children's behavioral conduct were mainly explained by masculinity, activity level, and responsibility. Responsibility turned out to be the strongest predictor of behavioral conduct among boys, while the activity level did among girls.

• Journal of the Korean Home Economics Association
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• v.8 no.1
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• pp.159-180
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• 1970

Forty-five home account books were randomized by electing "prize for good home manager" in 1967 through all over the country in korea. With this sampling analyzed monthly home expenditure in different item by test of significance, and compared with model of home expenditure and this results. Hope this analysis will help to the house wife for better plan home expenditure and will develope in scientific way of life in home managing. 1. Significance test of home account books in their items and in months indicated that there were significant statistical differences in the total living expenses. In other words, they did not work out a budget, and their home account books were nothing but a record expenses. 2. There was a significant difference in the monthly expenditure for food caused by the preparation of cabbage pickle (kim Jang) in November. This payment in a lump to the cabbage pickle brought about unbalance to home economic. 3. Compared with others, in November and in December we could find a meaningful difference in the monthly expenditure for clothing. 4. It was noted that there were not such comparable significant differences in months as to be mentioned for housing light and heating, education, saving, transportation and communication culture, taxes.