• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.473-480
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• 1996

Automatic fatigue crack length measuring system using DC electrical potential method and the system control program for automatic fatigue testing under random load condition were made in this study. And using these system and control program, fatigue tests were executed under constant and random load condition. As the result, the propagation of crack in random loading can be represented Paris equaiton and log normal probability function. But constant and random load test show different crack propagation properties.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.1
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• pp.36-48
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• 2021

As the material aging of nuclear power plants has been progressing in domestic and overseas, crack growth becomes one of the most important issues. In this respect, the crack growth assessment has been considered an essential part of structural integrity. The crack growth assessment for nuclear power plants has been generally performed based on ASME B&PV Code, Sec. XI but the idealization of crack shape and the conservative solutions of stress intensity factor (SIF) are used. Although finite element analysis (FEA) based on iterative crack growth analysis is considered as an alternative method to simulate crack growth, there are yet no guidelines to model the crack-tip spider-web mesh for such analysis. In this study, effects of various meshing factors on FE SIF calculation are systematically examined. Based on FEA results, proper criteria for spider-web mesh in crack-tip are suggested. The validation of SIF calculation method through mapping initial stress field is investigated to consider initial residual stress on crack growth. The iterative crack-tip modeling program to simulate crack growth is developed using the proposed criteria for spider-web mesh design. The SIF results from the developed program are validated by comparing with those from technical reports of other institutes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.6
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• pp.87-100
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• 2016

This research was performed for the purpose of providing useful and base data and preservation strategy of growth characteristics of Rhododendron micranthum. From the result of research, wild growth area of Rhododendron micranthum was discovered near steep forest road on 695~901m in altitude above sea level of Baekdu-daegan National Arboretum. Vegetation colony structure of Site I was resulted in Pinus densiflora(tree stratum M.I.P.=45.3%) is dominants, Betula schmidtii(arborescent M.I.P.=9.8%) is second dominant, and Site III resulted in Pinus densiflora(tree stratum M.I.P.=30.5%) is dominants, Betula schmidtii(arborescent M.I.P.=10.3%) is second dominant. Site II resulted in Betula schmidtii(arborescent M.I.P.=30.4%) is dominants and Pinus densiflora tree(tree stratum M.I.P.=8.3%) is second dominants. For herbs, it was researched that the rate of one year herb of chrysanthemum family(10), rice family(3), sedge(2) was higher than near forest area. Among Species diversity index, that of Shannon was in range of 0.7348~1.1090. After comparing this with similar area, this value was relatively low. Dominance analysis result was analyzed that various groups are evenly distributed. Monthly highest average temperature is $23.9^{\circ}$ in Site A and Site B, and monthly lowest average temperature is $-4.5^{\circ}C$ in Site I and $-4.7^{\circ}C$ in Site II. Monthly maximum average humidity is 85.6% in Site I and 83.2% in Site II. Monthly minimum average humidity is 60.9% in Site I and 60.8% in Site II and it showed that these 2 area are located far away but have similar temperature and humidity characteristic and climate environment is similar. It was analyzed that humidity is high with the result of annual average humidity is over 60%. In growth characteristic, it showed that doubt damage of Stephanitis pyrioides, exposure of roots, peeled bark was discovered and supplement on this is urgent.

• Journal of Ginseng Research
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• v.44 no.1
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• pp.168-177
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• 2020

Background: Ginseng has been widely used as a health-promoting tonic. Gintonin present in ginseng acts as a lysophosphatidic acid (LPA) receptor ligand that activates six LPA receptor subtypes. The LPA6 subtype plays a key role in normal hair growth, and mutations in the LPA6 receptor impair normal human hair growth. Currently, human hair loss and alopecia are concerning issues that affect peoples' social and day-to-day lives. Objective: We investigated the in vitro and in vivo effects of a gintonin-enriched fraction (GEF) on mouse hair growth. Methods: Human hair follicle dermal papilla cells (HFDPCs) and six-week-old male C57BL/6 mice were used. The mice were divided into the four groups: control, 1% minoxidil, 0.75% GEF, and 1.5% GEF. The dorsal hair was removed to synchronize the telogen phase. Each group was treated topically, once a day, for 15 days. We analyzed hair growth activity and histological changes. Results: GEF induced transient [Ca²⁺]_i, which stimulated HFDPC proliferation and caused 5-bromo-2'-deoxyuridine (BrdU) incorporation in a concentration-dependent manner. GEF-mediated HFDPC proliferation was blocked by the LPA receptor antagonist and Ca²⁺ chelator. HFDPC treatment with GEF stimulated vascular endothelial growth factor release. Topical application of GEF and minoxidil promoted hair growth in a dose-dependent manner. Histological analysis showed that GEF and minoxidil increased the number of hair follicles and hair weight. Conclusion: Topical application of GEF promotes mouse hair growth through HFDPC proliferation. GEF could be one of the main components of ginseng that promote hair growth and could be used to treat human alopecia.

• Korean Journal of Health Education and Promotion
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• v.27 no.4
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• pp.73-81
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• 2010

Objectives: The purpose of this study was to evaluate the effects of 12 weeks walking exercise program participation on changes in aging-related hormones concentration in elderly men. Methods: 16 elderly men(above 65 years old) were participated in 12 weeks walking exercise program by group types(exercise group ; n=8 & control group ; n=8), and their aging-related hormones(GH, testosterone and melatonin) levels were assessed before program(0 week) and after program(12 weeks). Regularly walking exercise program(field walking exercise) performed for 12 weeks(3days/week, 60~70min/day, HRR 55~65%). All data were expressed as mean and standard deviation by using SPSS/$PC^+$(ver. 13.0) program, and to evaluate the differences before and after treatment by groups, data were analyzed by paired t-test(a${\leq}$.05) and 2-way ANOVA was performed to examine the differences between groups and within groups by variables. Results and Conclusion: The conclusions obtained from this study were as follows ; In growth hormone. testosterone and melatonin response after 12 weeks exercise was increased significantly in walking exercise group(p<.01; p<.001; p<.001). And in result of 2-way ANOVA analysis for group, exercise, group${\times}$exercise, as compared with the exercise, there is significant difference in all items. Interaction effect of between group and exercise is difference significantly on GH(F=5.915, p<.05), testosterone(F=15.117, p<.01) and melatonin(F=8.131. p<.01) in all groups. We observed a direct relationship(positive improvement) between the regular physical activity and aging-related hormones(growth hormone, testosterone and melatonin concentrations) in elderly men.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.243-250
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• 2018

This study is a single-group experimental study to determine the effects on self-growth group programs are emotional intelligence and brain function index of Nursing Students. The data were collected between August 22 and September30, 2017. A total of 38 Nursing Students at k city were participated. The collected data were analyzed using frequency, mean and standard deviation, t-test, ANOVAs, and Repeated ANOVA. Self-growth group program showed differences in emotional intelligence over time and Emotional self-understanding showed a statistically significant difference between group and time. The brain function index is no statistically significant difference between group and time but showed a difference in time. The results of self - growing group program has a significant effect on the self - understanding of nursing college students and Brain function index. This study suggests the necessity that the self growth group program for self-understanding, others-understanding, self-opening of nursing students will help improve emotional intelligence.

• (The)Korea Educational Review
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• v.23 no.2
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• pp.5-30
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• 2017

In this study, we analyzed the longitudinal effect of participation in an overseas exchange student program on foreign language competence, intercultural competence, and personal development. Data were collected over three time points from the pre-, post-, and post-post tests with Korean college students who participated in an overseas exchange program. Hierarchical linear model was conducted to examine whether the change of participation effects exists over time and which predictors affected outcomes. The results of unconditional growth model showed that foreign language competence, cultural competence, and personal development showed statistically significant differences in their initial status prior to departure to participate in an overseas program as well as their growth rate. The results of conditional growth model showed that parents' level of education and overseas experiences before college affected the initial status of foreign language competence, and gender and overseas experience before college affected those of cultural competence as well as personal development. In case of growth rate, overseas experience before college and destination country/region affected foreign language competence, and interactions between Korean participating students and local students affected cultural competence. For personal development, only overseas experiences before college affected its growth rate. Lastly, relevant discussion and implications were provided.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.38-45
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• 2017

As the competitiveness of SMEs (small and medium enterprises) is getting more and more improved and globalized, the government provides various consulting services to secure the competitiveness of small and medium firms and support stable growth. However, the assessment of the result from the government's support is generally focused on non-financial factors, such as customer satisfaction and analysis of improvement effect. This paper is in regards to the statistical analysis of how much the government's support in the form of providing consulting services contributes to financial outcomes in terms of profitability and growth. ROA (return on asset) and ROS (return on sales), which are investment profitability and sales profitability respectively, are chosen as an indicator of profitability. For analysis of growth, sales revenue and total asset growth are used. The samples are 44 corporations which are supported by government, and 150 corporations which are selected for comparison, with corporate growth support center program by the Ministry of Trade, Industry, and Energy chosen as the consulting model. After gathering the yearly balance sheets and income statements of the samples from CRETOP, Korea Enterprise Data, the analysis is conducted in the way of identifying the statistical significance of financial difference in the same period between corporates taking consulting services and corporates which have not, and the difference of financial outcomes from the corporates taking consulting services before and after consulting services. As a result, in terms of business growth, it is turned out to have positive difference both in growth ratio and profitability compared to the compared corporations at the significant level. Therefore, it is obvious that the consulting program which government provides to SMEs have direct influence practically to the corporates' management performance.

• Fire Science and Engineering
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• v.34 no.3
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• pp.126-133
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• 2020

The purpose of this study was to investigate the effects of unconditional self-acceptance and self-exposure of trainees on the post-traumatic growth and to develop a program to achieve post-traumatic growth beyond the previous level without suffering from psychopathological consequences such as post-traumatic stress disorder I wanted to help. For this purpose, unconditional self-acceptance, self-exposure, and Korean post-traumatic growth scale were used. First, it was confirmed that unconditional self-acceptance and self-exposure of firefighters are correlated with post-traumatic growth. Second, hierarchical regression analysis showed that unconditional self-acceptance has more influence on self-acceptance and post-traumatic growth than self-acceptance of firefighters. Based on the results of this study, we propose the program development and therapeutic intervention strategies to promote post-traumatic growth of firefighters.

• Korean Journal of Social Welfare
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• v.41
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• pp.147-172
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• 2000

Although it has been noted that mentoring program is viewed as a effective way of intervention for the youth at-risk and vulnerable, few empirical studies have documented the benefits of mentoring program on youth. This research focused on effectiveness of campus-based mentoring program for children of unemployed families. It examined psychosocial benefits of mentoring program on mentor and mentee using the experimental design, posttest-only control group design. Significant differences were found between the control and intervention group. Children who have participated in mentoring program marked higher scores than control group in various psychosocial aspects including interpersonal skills, self-efficacy, sense of plan and motivation of schooling. Also university students who have participated as mentors marked higher ego-strength score than not. On the basis of these findings, this study recommended campus-based mentoring program as a effective growth-oriented program for the university students as well as the children of unemployed families.