• Journal of Service Research and Studies
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• v.14 no.2
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• pp.69-81
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• 2024

The The purpose of this study is to have a positive impact on the evaluation of the traditional market revitalization project by discussing the business details and implementation process of the commercial district revitalization project in depth. The research method uses practical methods for traditional market revitalization projects. First, the activation method of the place was examined through the concepts of Oldenburg's 'Third Place' and Carr et al.'s 'Five Demands for Public Space' and the theories related to non-face-to-face transactions were examined. The first study case was the commercial district revitalization project of the Cheongju Global Market Development Project(Seongan-gil Street Shopping Mall and Yukgeori traditional Market), which discussed revitalization of open space, revitalization through reproduction, and revitalization through festivals. The revitalization project through representation is a project to install a symbolic sculpture at the estimated location of the 'Namseokgyo' buried in Yukgeori traditional Market. The revitalization through the festival is the Korea Sale Festa, which is a vibrant business due to increased sales at traditional markets and shopping malls and floating population in open spaces. The second study case was the Cultural Tourism Promotion Project(Hanmin traditional Market), which discussed revitalization through the development of local brands and SNS content. In the conclusion, the relationship between the six projects and commercial district revitalization methods was discussed, and policy recommendations were made, mentioning the importance of reflecting regional characteristics in design planning. We hope that this study will be used to positively evaluate the traditional market revitalization project, showing that stakeholders are working hard to produce positive results within institutional limitations.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.103-111
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• 2024

Axial-flow fans are used to transport fluids in relatively low-pressure flow regimes, and a variety of design variables are employed. The tip geometry of an axial fan plays a dominant role in its flow and noise performance, and two of the most prominent flow phenomena are the tip vortex and the tip leakage vortex that occur at the tip of the blade. Various studies have been conducted to control these three-dimensional flow structures, and winglet geometries have been developed in the aircraft field to suppress wingtip vortices and increase efficiency. In this study, a numerical and experimental study was conducted to analyze the effect of winglet geometry applied to an axial fan blade for an air conditioner outdoor unit. The unsteady Reynolds-Averaged Navier-Stokes (RANS) equation and the FfocwsWilliams and Hawkings (FW-H) equation were numerically solved based on computational fluid dynamics techniques to analyze the three-dimensional flow structure and flow noise numerically, and the validity of the numerical method was verified by comparison with experimental results. The differences in the formation of tip vortex and tip leakage vortex depending on the winglet geometry were compared through a three-dimensional flow field, and the resulting aerodynamic performance was quantitatively compared. In addition, the effect of winglet geometry on flow noise was evaluated by numerically simulating noise based on the predicted flow field. A prototype of the target fan model was built, and flow and noise experiments were conducted to evaluate the actual performance quantitatively.

• Steel and Composite Structures
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• v.50 no.6
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• pp.705-720
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• 2024

Analyzing the collapse behavior of thin-walled steel structures holds significant importance in ensuring their safety and longevity. Geometric imperfections present on the surface of metal materials can diminish both the durability and mechanical integrity of steel shells. These imperfections, encompassing local geometric irregularities and deformations such as holes, cavities, notches, and cracks localized in specific regions of the shell surface, play a pivotal role in the assessment. They can induce stress concentration within the structure, thereby influencing its susceptibility to buckling. The intricate relationship between the buckling behavior of these structures and such imperfections is multifaceted, contingent upon a variety of factors. The buckling analysis of thin-walled steel shell structures, similar to other steel structures, commonly involves the determination of crucial material properties, including elastic modulus, shear modulus, tensile strength, and fracture toughness. An established method involves the emulation of distributed geometric imperfections, utilizing real test specimen data as a basis. This approach allows for the accurate representation and assessment of the diversity and distribution of imperfections encountered in real-world scenarios. Utilizing defect data obtained from actual test samples enhances the model's realism and applicability. The sizes and configurations of these defects are employed as inputs in the modeling process, aiding in the prediction of structural behavior. It's worth noting that there is a dearth of experimental studies addressing the influence of geometric defects on the buckling behavior of cylindrical steel shells. In this particular study, samples featuring geometric imperfections were subjected to experimental buckling tests. These same samples were also modeled using Finite Element Analysis (FEM), with results corroborating the experimental findings. Furthermore, the initial geometrical imperfections were measured using digital image correlation (DIC) techniques. In this way, the response of the test specimens can be estimated accurately by applying the initial imperfections to FE models. After validation of the test results with FEA, a numerical parametric study was conducted to develop more generalized design recommendations for the stainless-steel shell structures with the initial geometric imperfection. While the load-carrying capacity of samples with perfect surfaces was up to 140 kN, the load-carrying capacity of samples with 4 mm defects was around 130 kN. Likewise, while the load carrying capacity of samples with 10 mm defects was around 125 kN, the load carrying capacity of samples with 14 mm defects was measured around 120 kN.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.6
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• pp.135-154
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• 2023

Urban wetlands provide various ecosystem services and are subject to restoration and creation projects due to their increased value in the context of climate change. However, the vegetation structure of wetlands is sensitive to environmental changes, including artificial disturbances, and requires continuous maintenance. In this study, we conducted a vegetation survey of three wetlands created as part of a project to restore urban degraded natural ecosystems and monitored the quantitative changes in wetland vegetation structure using an unmanned aerial vehicle. The vegetation survey revealed 73 species in Incheon Yeonhui wetland, and the change in vegetation composition based on wetland occurrence frequency was 11.5% on average compared to the 2018 vegetation survey results. The vegetation survey identified 44 species in Busan Igidae wetland, and the proportion of species classified as obligate upland plants was the highest at 48.8% among all plants, while the proportion of naturalized plants accounted for 15.9% of all plants. The open water surface area decreased from 10% in May 2019 to 6.7% in May 2020. Iksan Sorasan wetland was surveyed and 44 species were confirmed, and it was found that the proportion of facultative wetland plant decreased compared to the 2018 vegetation survey results, and the open water surface area increased from 0.4% in May 2019 to 4.1% in May 2020. The results of this study showed that wetlands with low artificial management intensity exhibited a tendency for stabilization of vegetation structure, with a decrease in the proportion of plants with high wetland occurrence frequency and a relatively small number of new species. Wetlands with high artificial management intensity required specific management, as they had a large change in vegetation structure and a partially high possibility of new invasion. We reaffirmed the importance of continuous monitoring of vegetation communities and infrastructure for wetlands considering the function and use of urban wetlands, and restoration stages. These research results suggest the need to establish a sustainable wetland maintenance system through the establishment of long-term maintenance goals and monitoring methods that consider the environmental conditions and vegetation composition of wetlands.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.225-232
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• 2024

The reduction of CO₂ emissions in the energy production sector, which accounts for 86.8% of total greenhouse gas emissions, is important to achieve carbon-neutrality. At present, 60% of total power generation in South Korea is coal and natural gas. Replacing fossil fuel with renewable energy such as wind and solar has disadvantages of unstable energy supply and high costs. Therefore, this study was conducted through the co-firing of natural gas, ammonia and hydrogen utilizing the natural gas combined cycle process. The results demonstrated reduction in CO₂ emissions and 34%~238% of the power production compared to using only natural gas. Case studies on mass fractions of natural gas, ammonia and hydrogen indicated that power production and NO_x emissions were inversely proportional to the ammonia ratio and directly proportional to the hydrogen ratio. This study provides guidelines for the use of various fuel mixtures and economic analysis in co-firing power generation.

• Land and Housing Review
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• v.15 no.3
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• pp.141-151
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• 2024

This paper presents the results of an experimental study to evaluate the shear behavior of reinforced concrete beams reinforced with FRCM composites using different types of textile grids. It was found that the shear behavior of reinforced concrete beams with FRCM composites was observed by comparing the strains measured in the stirrups and textile grids. It was found that the ultimate strength of the strengthened specimens increased compared to the basic specimens, and the failure mode at ultimate strength changed from shear failure to bending failure. When the shear strength design values of the KDS 14 20 22 and AIJ ultimate strength types were compared with the actual experimental values, it was found that the AIJ ultimate strength type was more accurate. In addition, the shear contribution of FRCM composites in the A and T models was compared, and the results showed that both models had similar trends. Reflecting these results, it is recommended that further studies should be conducted to calculate the shear performance of beam members with FRCM composites and the shear contribution of FRCM composites by using the stirrup reinforcement ratio and the type of textile grid as variables.

• The Journal of Korean Society for School & Community Health Education
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• v.25 no.3
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• pp.39-49
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• 2024

Purpose: This study aims to analyze the current status of research related to infants and school-age-child published in the journal of Korean society for school & community health education from 2000 to 2023, with the goal of contributing to the future development and enhancement of the journal. Method: From 2000 to 2023, 52 papers were analyzed, comparing and classifying their journal topic, research types, data collection methods, and data analysis methods. Results: The results shows that the highest publication trend occurred between 2008 and 2012, with most studies focusing on school-age children. In terms of research topic, 'health behavior and health education' was the most frequent with 14 papers (26.9%), followed by oral health with 9 papers (17.3%), safety management with 7 papers (13.5%), and sexual awareness with 6 papers (11.5%). Quantitative research was the most common research type, with surveys being the primary data collection method. Descriptive statistics and t-test were the most frequently used data analysis methods. Conclusion: To enhance the quality of the journal of Korean society for school & community health education, there should be an expansion of evidence-based research focusing on infants and school-age children. Additionally, there is a need for greater diversity in research design, data collection, and analysis methods.

• Journal of Christian Education in Korea
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• v.77
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• pp.251-276
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• 2024

This study aimed to enhance the educational competencies of instructors and improve the quality of higher education by identifying instructing types, developing an assessment diagnostic tool, and designing a customized faculty training curriculum for each type. To achieve this, a literature review and Delphi research were conducted. The results are summarized as follows: First, instructing types such as 'Star Lecturer', 'Learning Mentor', and 'Designer' were identified through the analysis of previous studies. Second, a diagnostic tool for determining an instructor's type was developed by modifying and enhancing Grasha's Teaching Style Inventory, which is widely used both domestically and internationally. This tool comprises 24 questions, with 8 questions for each type. Third, a curriculum was designed for each instructing type, consisting of common courses necessary for all types and specialized courses tailored to the characteristics of each type. The common courses cover essentials for lesson design, implementation, and evaluation, while the specialized courses cater to the unique needs of each instructing type. Fourth, the developed model, tools, and curriculum underwent validation. A Delphi method was employed with a group of 10 experts, leading to revisions and finalizations based on their feedback. This study has laid the groundwork for instructors to identify their own teaching styles and receive customized training, thereby enhancing their teaching effectiveness and overall educational quality. However, further research is necessary to develop systems and mechanisms for the operationalization of these findings, including incentives for instructors and strategies for disseminating information among participants.

• Industry Promotion Research
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• v.9 no.3
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• pp.263-271
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• 2024

The present study examines the dual mediating role of social support and self-esteem in the relationship between grit and life satisfaction among college students. Utilizing a cross-sectional design, we surveyed a sample of 326 undergraduates from one university in China by means of purposive sampling. The analyses were conducted using SPSS PC+ Win. ver. 25.0 and SPSS PROCESS macro ver. 4.2. Pearson's correlation analysis was performed to show the correlations among the variables, and Model 6 of the PROCESS macro for SPSS was used to verify dual mediation effects. First, correlation results indicated positive and significant correlations between grit, social support, self-esteem and life satisfaction. Second, the dual mediating role of social support and self-esteem in the relationship between grit and life satisfaction was proved. This study contributes to the literature by elucidating the psychological mechanisms through which grit operates to enhance life satisfaction. The results have implications for the development of interventions aimed at fostering grit and the enhancement of social support and self-esteem to improve life satisfaction. Suggestions for future studies were discussed in detail.

• The Journal of Engineering Geology
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• v.34 no.3
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• pp.415-427
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• 2024

This study undertook a quantitative analysis of the distribution of fractures in deep drillcore from a Precambrian metamorphic complex on the north face of Hongcheon-gun, Gangwon-do, Korea. The fracture distribution with depth, inclination of fractures, and grain size in the fracture zone were measured and statistical techniques applied to derive probability distributions of fracture intervals. Analysis of the inclination angles of fracture planes showed that sub-horizontal fractures are dominant, and fracture spacing is mainly ≤0.5 m, with a median of 0.09 m, first quartile of 0.04 m, and third quartile of 0.18 m, indicating very dense fracture development. Statistical analysis of joint properties was undertaken with fitting using five probability density functions (double Weibull, exponential, generalized logistic, gamma, and lognormal). The lognormal distribution (sum of squared errors, SSE = 2.80) yielded the best fit based on the sum of residual squares. Quantitative characterization of the fracture characteristics of deep bedrock in the Hongcheon area is important for various geotechnical applications such as groundwater flow modeling, slope stability assessment, and underground structure design. In future studies, it will be necessary to combine in situ stress measurements and geophysical surveys to determine the relationship between fracture development and the local stress field.