• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6A
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• pp.417-424
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• 2011

This study focused on development of 60 m span PSC girder considering not only structural performance, but also economical efficiency and constructability including from the improvement of cross-section to the tendon profiles in sequence. Bulb-T type cross section was derived from optimization and actual possibilities to design a bridge were assessed through cross section evaluation. Tendons were also arranged efficiently so that the girder could resist the service load effectively. After developed girder was applied to a sample bridge, result of finite element analysis proved all load steps were satisfied with the allowable stress. Furthermore, it seemed that sufficient redundancy will be available to design a bridge safely. Based on these, a full-scale 60 m span girder was fabricated and 4 point bending test was performed. An initial crack occurred over twice of the service load in this experiment, which establishes adequate structural performance. 60 m span Half-Decked PSC girder developed in this study has a lower height for the given span which resulted from cross section improvement and efficient tendon layout. This girder also has not only the structural advantage, but also advantages in economical efficiency and constructability.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.173-183
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• 2012

Recently, experimental studies to prevent explosive spalling based on spalling mechanism and addition of Polypropylene fiber in high strength concrete (HSC) are performed actively. However, with respect to ultra high strength concrete (UHSC), its compact internal structure is more difficult release vapor pressure at rapid rising temperature compared to HSC. Therefore, in this study, an experiment was conducted to evaluate spalling properties of UHSC using ${\Box}$ $100mm{\times}100{\times}H200mm$ rectangular specimen according to ISO-834 standard fire curve. With respect melting point of fiber, three fiber types of Polyethylene, Polypropylene, and Nylon fibers with melting temperature of $110^{\circ}C$, $165^{\circ}C$, and $225^{\circ}C$, respectively, were considered. Mixed fiber of 0.15% and 0.25% of concrete volume was used to consider spalling properties based on water vapor pressure release. Then, TGDTA test on fiber and FEM analysis were performed. The results showed that it is difficult to prevent initial spalling without loss of fiber mass even if fiber melting temperature is low. Also, in preventing thermal spalling, fiber that melts to rapidly create porosity within 10 minutes of fire is more effective than that of low melting temperature property of fiber.

• The Korean Journal of Financial Management
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• v.26 no.3
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• pp.139-169
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• 2009

This paper introduces the modified VaR which takes into account the asymmetry and fat-tails of financial asset distribution, and then compares its out-of-sample forecast performance with traditional VaR model such as historical simulation model and Riskmetrics. The empirical tests using stock indices of 6 countries showed that the modified VaR has the best forecast accuracy. At the test of independence, Riskmetrics and GARCH model showed best performances, but the independence was not rejected for the modified VaR. The Monte Carlo simulation using skew t distribution again proved the best forecast performance of the modified VaR. One of many advantages of the modified VaR is that it is appropriate for measuring VaR of the portfolio, because it can reflect not only the linear relationship but also the nonlinear relationship between individual assets of the portfolio through coskewness and cokurtosis. The empirical analysis about decomposing VaR of the portfolio of 6 stock indices confirmed that the component VaR is very useful for the re-allocation of component assets to achieve higher Sharpe ratio and the active risk management.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.153-162
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• 2008

Purpose: Recombining bone morphogenetic protein (BMP) is usually acquiredfrom high level animals. Though this method is effective, its high cost limits its use. The purpose of this study was to evaluate the effect of bone morphogenetic protein-2 with protein transduction domain (BMP-2/PTD;TATBMP-2) on bone regeneration. Rat calvarial defect model and osteoblastic differentiation model using MC3T3 cell were used for the purpose of the study. Materials and Methods: MC3T3 cells were cultured until they reached a confluence stage. The cells were treated with 0, 0.1, 1, 10, 100, 500 ng/ml of BMP-2/PTD for 21 days and at the end of the treatment, osteoblastic differentiation was evaluated usingvon Kossa staining. An 8mm, calvarial, critical-size osteotomy defect was created in each of 48 male Spraque-Dawley rats (weight $250{\sim}300\;g$). Three groups of 16 animals each received either BMP-2/PTD (0.05mg/ml) in a collagen carrier, collagen only, or negative surgical control. And each group was divided into 2 and 8 weeks healing intervals. The groups were evaluated by histologic analysis(8 animals/group/healing intervals) Result: In osteoblastic differentiation evaluation test, a stimulatory effect of BMP-2/PTD was observed in 10ng/ml of BMP-2/PTD with no observation of dose-dependent manner. The BMP-2/PTD group showed enhanced local bone formation in the rat calvarial defect at 2 weeks. New bone was observed at the defect margin and central area of the defect. However, new bone formation was observed only in 50% of animals used for 2weeks. In addition, there was no new bone formation observed at 8 weeks. Conclusion: The results of the present study indicated that BMP-2/PTD(TATBMP-2) have an positive effect on the bone formation in vitro and in vivo. However, further study should be conducted for the reproducibility of the outcomes.

• Journal of Home Health Care Nursing
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• v.8 no.1
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• pp.50-61
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• 2001

With the improvement of current medicine, the number of the chronicly ill children are increasing. The illness of the child drives all of the family to despair. especially it is a burden on the mother who takes care of the ill child. She's faced with many emergencies and feels powerless. The home care for a child is for finding a child's problems early and mediating them. The purpose of this study was to investigate the mother's reaction following their chronicly ill child's discharge and to investigate the supporting needs for caring for an ill child. The subjects of this study were mothers with a chronicly ill child being discharged from a general hospital in Seoul and the data was collected from July 20 to September 30. Data was collected by using questionnaires which were developed by the researcher. (The questionnaires were composed of the average 5 points - Likert's method). The Mother's reaction means that the higher the score, the more negative the mother's thoughts about discharge are. Supporting need for caring for ill an child means that the higher the score, the higher the demand of nursing is. The statistical analysis used the SPSS program for t-test. ANOVA, and Pearson Correlation. The results of this study were as follows: 1. The mother's reaction scores following discharge were the lowest. 19 and the highest 72 so that the total average was 43.15. The answer, 'I worry that my baby will be troubled with illness again after discharge gained the high points (3.94 of 5 points). The answer. 'The discharge of my baby makes me gloomy' gained 2.05-it was the lowest points. Their were significant differences according to religion (p=.006). salary (p=.050). the burden of the medical fee (p = .005) and caregiver (p=.027). 2. Supporting Need for caring for ill an child was the lowest 15 and the highest 67. the total average was 47.87. The answer. 'I'd be glad to get a person whom I could always get counsel about the health of my baby with' scored the high point (average 4.04 of 5). The answer. 'Caring for my baby at home makes me exhausted' gained the lowest point. 2.49. Their were significant differences according to religion (p=.019) and diagnosis (p=.019). 3. The relationship between the reaction of the mother and supporting need for caring for an ill child was a positive correlation (r=0.585). In conclusion. this study revealed that mothers weren't positive about their chronicly ill child's discharge and they wanted to get support for caring for an ill child. Through this study. I proposed that the program to support the chronicly ill child at home and home care by continuous counselling after discharge should be develop.

• Journal of Korean Home Economics Education Association
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• v.31 no.4
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• pp.115-128
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• 2019

The purpose of this study was to examine the influence of self-esteem and consumer socialization agents on rational consumption patterns of middle school students. Using a convenient sampling method, the data were collected from middle schools in Seoul, Gyeonggi, Chungcheong, Jeonnam, and Gwangju and a total of 412 copies were analyzed. The descriptive statistics, Chronbach's α, t-test, and stepwise regression analysis were performed using the SPSS and the results were as follows. First, rational consumption behavior was 3.18 and self-esteem was 3.54 on a 5-Likert scale. As for consumer socialization agents, parents was the highest at 3.13, followed by school 2.83, mass media 2.78 and peers 2.73. Second, the average comparison of rational consumption behavior and consumer socialization agents by gender showed that there was no gender difference in rational consumption behavior, but in the case of consumer socialization, girls were higher than boys. Third, examining the influence of self-esteem and consumer socialization agents on rational consumption behavior, it was found that the amount of money, mass media, and peers showed an negative effects on rational consumption behavior, while self-esteem and parents showed positive effects on rational consumption behavior. In this regard, middle school students need to have more self-esteem and guide their peers so that their influence can be positive in the home economics class in order to become consumers with rational consumption behavior.

• 대한공업교육학회지
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• v.43 no.2
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• pp.43-60
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• 2018

The purposes of this study are to compare practical ability of vocational education high school, investigate effectiveness of recruitment practical examination, and provide basic data that can be helpful to recruit teaching staffs of occupational training institution in the middle stage and strengthen practical guidance capability of teacher through the analysis by variables of teacher's background. To achieve them, concrete capability areas related to practical ability were conceived and differences of new teacher's abilities were compared between area that fulfilled recruitment practical examination and areas that didn't fulfill. The conclusions of this study are as follows. First, practical abilities among specialized subject teachers of vocational education high school were compared by existence of vocational education high school teacher recruitment practical examination. As a result, the average of practical ability of the group who was fulfilled by recruitment practical examination was somewhat high in all of 5 sub-areas for practical ability, but wasn't significant statistically. Second, the differences of practical ability by background variable among specialized subject teacher of vocational education high school were compared. As a result, the group who possesses national technology licence, existence of short-term teaching career, teaching course completion form of open teacher training showed higher average and it showed significant differences statistically.

• Journal of the Korean School Mathematics Society
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• v.22 no.4
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• pp.369-393
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• 2019

The purpose of this study is to find the commonality between process-focused assessment and existing performance evaluation and to find out whether the process-focused assessment is effective for the development of the character of school mathematics. By analyzing the previous research, this study defined the meaning of process-focused assessment as an evaluation that can improve students' growth and quality of class through immediate feedback by introducing various performance tasks and evaluation methods. The character of school mathematics refers to personality factors that are easily expressed and cultivated during math classes. Therefore, this study presented examples of the feasibility of process-focused assessment focusing on geometry and vector subjects and examined the effectiveness of mathematics and character development through process-based evaluation. Four course-based assessments (math experiments, logic, proof, and communication) aimed at cultivating the character of school mathematics were conducted from March to June 2019 for the third year of high school. The index was measured. Analysis of the results using the corresponding variable t-test showed that the process-based evaluation in this study had a significant effect on the character of school mathematics development.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.201-210
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• 2017

Scutellariae baicalensis (S. baicalensis) has been traditionally used for anti-inflammatory effect. This study was designed to compare the antioxidant and whitening effects of S. baicalensis extract and its fermented extract by Leuconostoc mesenteroides (L. mesenteroides). Fermented extract of S. baicalenins was prepared by inoculation of L. mesenteroides after the extraction procedure with 70% ethanol. S. baicalensis extract and its fermented extract was investigated via high-performance liquid chromatography (HPLC). Simultaneous qualitative analysis of two bioactive components; baicalin and baicalein was achieved by comparing their retention times ($t_R$) and UV spectra with those of the standard components. Cell viability test results indicated that both S. baicalensis extract and its fermented extract were non-toxicity. In DPPH radical scavenging ability, $SC_{50}$ values of the fermented extract was $34.43{\mu}g/mL$ as a result of more effective than S. baicalensis extract. In nontoxic concentration rage, fermented extract of S. baicalensis showed strong melanin production inhibitory effect in ${\alpha}$-melanocyte stimulating hormone (MSH)-stimulated B16F10 cell ($IC_{50}=68.17{\mu}g/mL$). These results suggested that fermented extracts of S. baicalensis has considerable potential as a cosmetics ingredient with an antioxidant and anti-wrinkle and whitening effects.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.2
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• pp.191-200
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• 2018

In this study, we conducted research to find anti-wrinkle skin care ingredients from natural sources via the measurement of procollagen type 1 levels in the medium of normal human dermal fibroblast (NHDF) and found that a Nelumbo nucifera leave extract (NLE) was as the best effective ingredient. By the high performance liquid chromatography analysis, we confirmed isoquercitrin was one of the main compounds of NLE. Moreover, it also increased the procollagen type 1 production without cytotoxicity of NHDF. NLE and isoquercitrin exerted free radical scavenging activity. Especially, isoquercitrin exhibited strong intracellular antioxidant capacity in human skin-derived cells, HaCaT and NHDF. Finally, we performed clinical test for the inhibitory effect of NLE on skin wrinkle formation. A randomized study was conducted in 22 healthy female volunteers, aged between 30 and 65 yrs, with moderate to moderately severe facial wrinkles. Volunteer applied a 1.7% NLE cream (isoquercitrin 51 ppm) and a control cream at each facial side (left/right) twice daily for 8 weeks. The 1.7% NLE cream improved skin roughness through reducing the wrinkle of the craw's feet significantly without any skin side effect. Our results demonstrate that NLE and isoquercitrin can increase the collagen production and exert antioxidant activity. Therefore, we expect that the new non-toxic herbal extract, isoquercitrin-containing NLE will be interesting natural ingredient of cosmetics with anti-wrinkle efficacy.