• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.76-85
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• 2017

In this study, to evaluate the mechanical properties of fiber-reinforced cement composites by strain rate, hydraulic rapid loading test system was developed. And compressive and tensile strength of the hooked steel fiber and polyamide fiber reinforced cement composite were evaluated. As a result, the compressive strength, strain capacity and elastic modulus were increased with increasing strain rate. The effect of compressive strength by type and volume fraction of fibers was not significant. The dynamic increase factor(DIF) of the compressive strength was higher than that of the CEB-FIP model code 2010 and showed a trend similar to that of ACI-349. The tensile strength and strain capacity were increased with increasing strain rate. The hooked steel fibers were drawn from the matrix. The tensile strength and strain capacity of hooked steel fiber reinforced cement composites were increased as the strain rate increased. The tensile strength and deformation capacity of the fiber reinforced cement composites were increased. And, hooked steel fibers were drawn from the matrix. On the other hand, because the bonding properties of polyamide fiber and matrix is large, polyamide fiber was cut-off with out pullout from matrix. The strain rate effect on the tensile properties of polyamide fiber reinforced cement composites was found to be strongly affected by the tensile strength of the fibers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.152-161
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• 2017

The purpose of this study was to establish a model for the structural relationship between the participation motivation and flow experience, self-achievement and life satisfaction in windsurfers. The subjects in this study were 206 selected male and female adults who windsurfed on a beach in Yangyang-gun, Gangwon Province. The statistical packages SPSS 20.0 and AMOS 16.0 were used to conduct the statistical analysis of the collected data. First, the participation motivation of the windsurfers exercised a significant influence on their flow experience(t=18.156, p<.001). Second, the participation motivation of the windsurfers had a significant impact on their self-achievement(t=19.848, p<.001). Third, the participation motivation of the windsurfers affected their life satisfaction in a significant way(t=8.219, p<.001). Fourth, the flow experience of the windsurfers impacted on their self-achievement in a significant manner (t=9.769, p<.001). Fifth, the flow experience of the windsurfers had no significant impact on their life satisfaction(t=16.033, p<.001). Sixth, the self- achievement of the windsurfers didn't exert any significant influence on their life satisfaction(t=17.438, p<.001). The findings of this study can be used to help windsurfers improve their quality of life.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.380-390
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• 2017

This study examined the relationship between social support, social participation and physical functioning among older adults in community senior centers. The subjects of this study were 194 persons aged 60 years or older who participated in the senior center in K province and D city, from June 16 to June 30, 2016. The collected data were analyzed using descriptive statistics, T-test, one way ANOVA, Pearson correlation analysis, multiple regression analysis, and structural model analysis using IBM SPSS Statistics 23.0 and IBM AMOS 21.0. The result showed that the social support and physical functioning of the elderly in the community were above normal, and social participation was somewhat low. Interestingly, an analysis of the physical functioning between social support, social participation and depression revealed significant correlations. The factors affecting the physical health were 23.4% of the respondents who had a significant influence on social support and leisure activities. In addition, the result of structural model analysis showed that social support had a significant influence on the social participation, depression and physical functioning. Therefore, the results suggests that the development of educational programs and an age-friendly environment should be actively provided to older adults in the community by strengthening the physical function through social support for active ageing.

• Journal of agricultural medicine and community health
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• v.47 no.4
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• pp.242-254
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• 2022

Purpose: This study was designed to test structural equation modeling of the quality of life of elderly diagnosed dementia living in the community in order to provide guidelines for development of intervention and strategies to improve their quality of life. Methods: The participants in the study were elderly who visited the public health center in C rural between May 30 and september 15, 2017. Data collection was carried out through one-on-one interviews. Demographic factors, knowledge, Attitude, Self-Efficacy, social support, accessibility, request for Information, health practice, depression, subjective memory complaints, dependence scale and quality of life were investigated. Results: The final analysis included 192 elderly. Fitness of the hypothesis model was appropriate(χ²=192.89, p=.000, GFI=0.90, SRMR=0.08, NNFI=0.94, CFI=0.95, PNFI=0.72, RMSEA=0.07). Depression, subjective memory complaints and dependence were found to be significant explaining varience in quality of life. Social support, dementia preventive behavior and health practice had an indirect effect on the quality of life. Conclusions: To improve the quality of life of elderly diagnosed dementia living in the community, comprehensive interventions are necessary to manage knowledge, attitude, self-efficacy, social support, health practice, depression, subjective memory complaints and dependence that can contribute to enchance the quality of life of elderly diagnosed dementia living in the community.

• Journal of the Korean Geotechnical Society
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• v.38 no.12
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• pp.45-65
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• 2022

In this paper, a diaphragm wall that supports soils and rock was modeled using FLAC, a finite difference analysis program, to evaluate the seismic behavior of temporary retaining structures in a deep excavation. The appropriateness of the numerical model was verified by comparing its results with those of the centrifuge test performed in a similar condition. The bending moment distribution along the diaphragm wall shows a very similar tendency, and the maximum acceleration obtained at the backfill and top of the wall shows a difference within 5%. Based on the developed model, a parametric study was conducted in various input earthquake, ground, and excavation conditions. The maximum structural forces and bending moment under earthquake loading were compared with the maximum values during excavation, from which the critical condition that requires a seismic design was roughly sorted out. The maximum bending moment of a wall that retains soil layers increased 17%. Particularly, the axial force of struts located in loose soils increased 32% under 100 years return period of an earthquake event, which strongly is estimated to require seismic design for structural safety.

• Economic Analysis
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• v.27 no.1
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• pp.67-90
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• 2021

This study found an interesting fact that the nonlinear relationship structure between volatility and trading volume changed before and after the COVID-19 pandemic according to empirical analysis using Bitcoin (BTC) market data that sensitively reflects investors' trading behavior. That is, their relationship appeared positive (+) in a stable market state before COVID-19 pandemic, as in theory based on the information flow paradigm. In a state under severe market stress due to COVID-19 pandemic, however, their dependence structure changed and even negative (-). This can be seen as a consequence of increased market stress caused by COVID-19 pandemics from a behavioral economics perspective, resulting in structural changes in the asset market and a significant impact on the nonlinear dependence of volatility and trading volume (in particular, their dependence at extreme quantiles). Hence, it should be recognized that in addition to information flows, psychological phenomena such as behavioral biases or herd behavior, which are closely related to market stress, can be a key in changing their dependence structure. For empirical analysis, this study performs a test of Ross (2015) for detecting a structural change, and proposes a Copula Regression Quantiles (CRQ) approach that can identify their nonlinear relationship structure and the asymmetric dependence in their distribution tails without the assumption of i.i.d. random variable. In addition, it was confirmed that when the relationship between their extreme values was analyzed by linear models, incorrect results could be derived due to model specification errors.

• Korea Trade Review
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• v.41 no.2
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• pp.159-183
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• 2016

This study focuses on export venture firms in Daedeok Innopolis and examines the structural relationships among dynamic capability, technology commercialization competence, innovation performance, and competitive advantage. In particular, this study attempts to analyze dynamic capabilities that may affect technology commercialization competence, innovation performance, and competitive advantage. The development of the research model takes on a dynamic-capability view and is based on empirical studies regarding competitive advantage. A survey of 103 export venture firms was conducted from January 5, 2015, to February 4, 2015. A partial least squares structural equation model is used to test the relationships between constructs set in the study. The results of the study show that the dynamic capability of an export venture firm has a significant positive influence on the firm's technology commercialization competence, innovation performance, and competitive advantage. The study also finds evidence that the export venture firm's technology commercialization competence directly affects its innovation performance and competitive advantage. In addition, the findings indicate that the innovation performance of an export venture firm has a significant positive impact on the firm's competitive advantage. Overall, these findings contribute to a better understanding of the contexts in which dynamic capability represents a specific capability for export venture firms.

• Korea Trade Review
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• v.42 no.2
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• pp.319-344
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• 2017

The international standard certification evaluates the extend to which the supplier satisfies the international standard certification standards of the supplier of the product and the service, recognizes the quality assurance ability and reliability of the supplier, thereby resolving the international trade regulation that can occur to various fields and strengthening the network of the global partnership it is making an important contribution. Therefor, in this study, the survey was conducted on 153 companies of Korean import and export companies. The research method was empirically analyzed by the structural equation model. The results of the hypothesis test of this study are as follows. First, resource management factors among the international standard certification factors in the global trade supply chain integration had a positive effects on CRM satisfaction. Second, the measurement, analysis and improvement factors of international standard certification factors had a positive effects on CRM satisfaction. Third, CRM satisfaction has a positive effects on business performance. Through this study, it is concluded that the Korean import and export companies have an important role in improving the business performance of the global trade partners.

• The Korean Journal of Franchise Management
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• v.8 no.2
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• pp.25-36
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• 2017

Purpose - Recently, entrepreneurship education has been revitalized with interest in entrepreneurship. Entrepreneurship education is an educational service activity that is provided for entrepreneurship and individual start-up success within a certain period of time. According to previous studies on entrepreneurship and entrepreneurship, the satisfaction of entrepreneurship education affects entrepreneurship and as a result increases entrepreneurship. In recent years, the number of female entrepreneurs has also increased as the number of entrepreneurial issues has increased. Based on previous studies, this research proposed the theoretical framework about the structural relationships among mentoring quality (career development, psychological social, role modeling), education satisfaction, recommendation intention and entrepreneurial intention. This study is to find out the possibility of attempting to create a theoretical basis for entrepreneurial mentoring education in entrepreneurship education program. Research design, data, and methodology - In this model, mentoring quality consists of three sub-dimensions such as career development, psychological social, and role modeling. In order to test research model and hypotheses, the data were collected from 203 female college students who participated in entrepreneurial education. The data were analyzed using frequency analysis, confirmatory factor analysis, correlation analysis, and structural equational modeling with SPSS 24.0 and SmartPLS 3.0 statistical program. Result - The results of the study are as follows. First, role modeling has a positive effect on recommendation intention and entrepreneurial intention. Second, career development has a strong negative effect on the entrepreneurial intention. Third, career development and role modeling had a positive effect on educational satisfaction, and educational satisfaction had positive influence on recommendation intention and entrepreneurial intention. Conclusions - As women's social advancement becomes more active, start-up support programs including entrepreneurship mentoring are increasing. The results of this study suggest how to use the mentoring program mix and how to allocate the resources for the education program when the entrepreneurial education manager plans and executes the mentoring education program. For example, this study shows that career development and role modeling enhance educational satisfaction, and in turn increase recommendation intention and entrepreneurial intention. This means that entrepreneurship education should consist of contents that include career development functions such as sponsorship, guidance, protection, and provision of challenging work. In addition, the findings of this study indicate that mentors should perform the function of allowing the participants to have confidence and professional thinking ability at the time of start up based on their experiences.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.121-130
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• 2007

In this paper, large scale experimental model tests were performed to investigate the distribution of earth pressure acting on embedded rigid pipes having different bedding conditions. For these tests, very light weighted EPS blocks were installed at top and bottom of the rigid pipe and Jumunjin Standard Sand was used as a ground material. As results of model tests, for the case of no bedding on the pipe, the measured pressure at the bottom of the pipe was $4.96_{tf/m^2}$ whereas they were in the range of $1.87{\sim}4.96_{tf/m^2}$ in the case of EPS beddings being installed at the top and the bottom of the pipe. Therefore, for the case of EPS bedding being installed, the ratio of reduced pressures acting on the pipe, compared with the case of no EPS beddings, were in the rage of 16~62%. As a result of parametric test with changing the locations of EPS bedding, the trend of reducing the stress acting on the pipe was in the order of bottom bedding, top bedding, and top and bottom bedding. Effect of bedding positions on the reduced magnitude of acting pressure on the pipe was more significant in the case of top bedding than in the case of the bottom bedding.