• Korean Journal of Materials Research
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• v.31 no.6
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• pp.345-352
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• 2021

In this study, Ni nanoparticle supported by graphene oxide (GO) (Ni-GO) is successfully synthesized through hydrothermal synthesis and calcination, and Cr(VI) is extracted from aqueous solution. The morphology and structure of Ni-GO composites are characterized by scanning electron microscopy (SEM), trans mission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). High-resolution transmission electron microscopy (HRTEM) and XRD confirms the high dispersion of Ni nanoparticle after support by GO. Loading Ni on GO can obviously enhance the stability of Ni-GO composites. It can be calculated from TGA that the mass percentage of Ni is about 60.67 %. The effects of initial pH and reaction time on Cr(VI) removal ability of Ni-GO are investigated. The results indicate that the removal efficiency of Cr(VI) is greater than that of bared GO. Ni-GO shows fast removal capacity for Cr(VI) (<25 min) with high removal efficiency. Dynamic experiments show that the removal process conforms to the quasi-second order model of adsorption, which indicates that the rate control step of the removal process is chemical adsorption. The removal capacity increases with the increase of temperature, indicating that the reaction of Cr(VI) on Ni-GO composites is endothermic and spontaneous. Combined with tests and characterization, the mechanism of Cr(VI) removal by rapidly adsorption on the surface of Ni-GO and reduction by Ni nanoparticle is investigated. The above results show that Ni-GO can be used as a potential remediation agent for Cr(VI)-contaminated groundwater.

• The Journal of the Korea Contents Association
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• v.22 no.7
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• pp.307-317
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• 2022

The purpose of this study was to examine the mediating effect of self-efficacy in the relationship between perceived family function and depression in the elderly. A self-reported questionnaire was conducted from July 1, 2019 to July 31, 2019, and 296 copies were used for data analysis. For data analysis, frequency analysis, descriptive statistics, and correlation analysis were performed, and a structural equation model was used to verify the effectiveness of parameters. Results, as the main results, first, family function and self-efficacy of the elderly were found to have a negative effect on depression, and it was confirmed that family function had a positive effect on self-efficacy. Second, it was confirmed that there is a mediating effect of self-efficacy between family function and depression in the elderly. Social interventions for improving self-efficacy in the elderly are suggested to be developed in order to reduce depression in the context. A further discussion on this has been presented.

• Journal of Creative Information Culture
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• v.6 no.2
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• pp.77-88
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• 2020

The purpose of this study is to statistically analyze the correlation between CS Unplugged education and the computational thinking of gifted and talented students. In this study, qualitative research was conducted for 17 students in 5th grade gifted class at an elementary school in the city of Yongin. Students participated in 10 hours of CS unplugged classes. Student questionnaire, class journals, student activity sheets, and student interview records were collected and qualitatively analyzed. In order to supplement the qualitative data, computational thinking ability tests were also administered. The results of the study are as follows. First, CS unplugged education plays an effective role in improving CT of gifted and talented students. Second, it was not every sub-area of CT that CS unplugged education brought statistically significant improvements in. Third, CS unplugged education is suitable to be presented as the first step of the SW curriculum for gifted and talented students.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.816-826
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• 2022

The purpose of this study is to examine the effect of improving academic self-efficacy and self-directed learning ability by conducting a self-directed learning program for college students. To this end, a program was conducted for 28 college students. In order to examine the effectiveness of the program, a single-group pre-post design method was used, which compared the pre-score before the program and the post-score after the program. The program was conducted during the 8 session. The research results are as follows. First, the pre-post scores of the academic self-efficacy of the students who participated in the program increased, but it was not statistically significant. Second, the pre-post score of the self-directed learning ability of students who participated in the self-directed learning program increased significantly. Through these results, the implications of the self-directed learning program for college students and suggestions for follow-up research were presented.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.1
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• pp.149-155
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• 2022

Purpose : This study investigated the effects of wearing a mask and different mask filters on the respiratory function of stroke patients. Methods : A total of 15 stroke patients were selected according to the inclusion and exclusion criteria. The respiratory functions were compared between participants with and without masks and among respiratory functions with three different mask filters. The order of using masks was non-wearing masks, Dental masks, KF80 masks, and KF94 masks; the difference in respiratory volumes among these conditions were measured. For accuracy of the measurement, sufficient education on the respiratory measurement method was provided to the researcher, and the heart rate of the participants was estimated to confirm their stability before the measurements. To ensure accuracy, the subjects were educated on the researchers' respiratory measurement methods. Each measurement was followed by 10 min breathing stability before replacing the next mask. Results : The results of this study showed that the difference in respiratory functions, including forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁), and maximal voluntary ventilation (MVV), in stroke patients was statistically significant among different masks (p<.05). Afterwards, the values of FVC, FEV₁, and MVV in stroke patients wearing masks were significantly lower than those of the non-masked control group (p<.05). The difference in respiratory functions with different mask filters showed no statistical significance (p<.05). Conclusion : This study showed that participants wearing any of the masks presented a lower respiratory function than that of those without using masks; additionally, no difference in respiratory functions was observed with differences in mask filters. Therefore, wearing a mask for a prolonged period is confirmed to affect breathing in stroke patients with weak respiratory function.

• Asia-Pacific Journal of Business
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• v.13 no.3
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• pp.183-208
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• 2022

Purpose - The main purpose of this study is to widely investigate the impact of recent pandemic crises on the synchronization of the world capital markets through 25 stock indices from major developed countries. Design/methodology/approach - This study collects 25 stock indices from major developed countries and the time period is between January 5, 2001 and February 24, 2022. The data sets used in the study include finance.yahoo.com and Investing.com.. The Granger causality analysis, unit-root test, VAR analysis, and forecasting error variance decomposition were hired in order to analyze the data. Findings - First, there are significant inter-relations among 25 countries around recent major pandemic crises(such as SARS, A(H1N1), MERS, and COVID19), which is consistent result with previous literature. Second, COVID19 shows much stronger impact on the world-wide synchronization than other pandemics. Third, the return volatility of each stock market varies, unit root tests show that daily stock index data are unstable while daily stock index returns are stable, and VAR(Vector Auto Regression) analyses presents significant inter-relations among 25 capital markets. Fourth, from the impulse response function analyses, we find that each market affects the other markets for short term periods, about 2~4 days, and no long term effect was not found. Fifth, Granger causality tests show one-side or two-sides synchronization between capital markets and we estimate, through forecasting error variance decomposition method, that the explanatory portions of each capital market on other markets vary from 10 to 80%. Research implications or Originality - The above results all together show that pandemic crises have strong effects on the synchronization of world capital markets and imply that these synchronizations should be carefully considered both in the investment decisions by individual investors and in the financial and economic policies by governments.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.216-224
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• 2021

Purpose: Global collaboration to accelerate development and equitable access to COVID-19 tests, treatments, and vaccines was launched with the name of the Access to COVID-19 Tools Accelerator (ACT-A), and this initiative owes its expertise to the lessons learned of the global health organizations. To date, the comprehensive mechanisms and potential effects of the initiative remain largely unknown. Methods: This study reviewed the programs of Gavi, the Global Fund, Unitaid, and ACT-A, which mitigating barriers to greater use of health technology with an analytic framework. Results and conclusion: The study findings are as follows. First, programs to alleviate the absence of necessary technology include the International Finance Facility for Immunization and Covax Facility. Second, Pooled Procurement Mechanism and Accelerated Order Mechanism are examples of mitigating the inability to access technology. Third, programs to overcome reluctance to adopt accessible technology include health system strengthening efforts such as the capacity-building health workforces. Further actions of Korea are needed to collaborate with the initiatives to enhance health outcomes.

• Wind and Structures
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• v.34 no.1
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• pp.15-27
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• 2022

This work comes within the framework of the "Benchmark on the Aerodynamics of a Rectangular Cylinder" that investigates a rectangular cylinder of length-to-depth ratio equal to 5. The present study reports and discusses velocity fields acquired using planar Particle Image Velocitmetry for several angles of attack and Reynolds numbers. In particular, for a cylinder depth-based Reynolds number of 2 × 10⁴ and zero incidence angle, the flow features along the lateral (parallel to the freestream) upper and lower surfaces of the cylinder are reported. Using first and second order statistics of the velocity field, the main flow features are discussed, especially the size and location of the time-averaged flow structures and the distribution of the Reynolds stresses. The variation of the flow features with the incidence is also studied considering angles of attack up to 6°. It is shown that the time-averaged flow is fully detached for incidence higher than 2°. For an angle of attack of 0°, the effects of the Reynolds number varying between 5 × 10³ and 2 × 10⁴ are investigated looking at flow statistics. It is shown that the time-averaged location of the reattachment point and the shape and position of the time-averaged main vortex are mostly constant with the Reynolds number. However, the size of the inner region located below the time-averaged shear layer and just downstream the leading edge corner appears to be strongly dependent on the Reynolds number.

• Journal of Korea Trade
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• v.25 no.3
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• pp.153-168
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• 2021

Purpose - In this study, we aim to explore new distribution strategies for sustainable growth in the era of the 4th industrial revolution, focusing on SMEs (small and medium-sized enterprises) in Korea, and suggest ways to upgrade the government's official distribution channel to the next level. Design/methodology - First of all, this paper explored the prior research, the current status of sales support for SMEs, and the changes in the distribution industry due to COVID-19 pandemic. Based on Moon (2016)'s ABCD strategic model - Agility, Benchmarking, Convergence, and Dedication, the study then derived directions in which official distribution channels should move and the new distribution strategy for Korean SMEs to secure competitive advantage. Findings - First, in terms of 'Agility', in order to upgrade official distribution channels, which are currently at some competitive disadvantages compared to private distribution companies, we must quickly introduce technologies for the 4th industrial revolution, such as AI, Big Data, etc., and establish precise strategies to strengthen the capabilities of SMEs. Second, in terms of 'Benchmarking', the use of "Chamelezones" has been increasing to enhance the competitiveness of offline stores in line with recent ontact trends. Therefore, official distribution channels should also benchmark such cases, strengthening their competitiveness by utilizing offline spaces more efficiently and effectively. Third, in terms of 'Convergence', in line with the rapidly changing trend of the times, official distribution channels should also promote active partnerships with media commerce, e-commerce and ICT platforms, as well as cooperation with private retailers, and focus on creating synergy effects through them. Finally, from the perspective of 'Dedication', digitalization should be promoted step by step, finding the sector that can accelerate digital among the value chains of official distribution channels, and continuing to discuss how to digitize it realistically. Originality/value - Based on this analysis, we have presented strategies and implications for innovating official distribution channels for SMEs, which will contribute to enhancing the competitive advantage of official distribution channels in the post COVID-19 pandemic era.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.662-675
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• 2021

In order to evaluate the effectiveness of the Jeollabuk-do social welfare errand center, this study focused on identifying the effects of users' personal characteristics and workers' job environment characteristics on user satisfaction. The data analyzed are survey data collected from users and workers at 11 social welfare errand centers in each city and county in Jeollabuk-do. In the detailed analysis, the first-level independent variable for the users' personal characteristics, the second-level independent variable for the worker's job environment characteristics, and the user satisfaction were set as the dependent variables, and then a hierarchical linear model analysis model was applied. As a result of the analysis, it was confirmed that households with disabilities, sense of job value, job stress, role overload, and salary satisfaction had a significant effect on the service satisfaction of users. The results of this analysis show that the characteristics of the job environment of the workers have a major effect on the satisfaction of service users. This suggests that there is a strong need for improvement in the fields.