• Advances in concrete construction
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• v.8 no.3
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• pp.239-246
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• 2019

Substitution of natural fine aggregates with industrial by-products like precious slag balls (PS Balls) offers various advantages like technical, economic and environmental which are very important in the present era of sustainability in construction industry. PS balls are manufactured by subjecting steel slag to slag atomizing Technology (SAT) which imparts them the desirable characteristics of fine aggregates. The main objective of this research paper is to assess the feasibility of producing good quality concrete by using PS balls, to identify the potential benefits by their incorporation and to provide solution for increasing their utilization in concrete applications. The study investigates the effect of PS balls as partial replacement of fine aggregates in various percentages (20%, 40%, 60%, 80% and 100%) on mechanical properties of concrete such as compressive strength, splitting tensile strength, and flexural strength. The optimum mix was found to be at 40% replacement of PS balls with maximum strength of 62.89 MPa at 28 days curing. Permeability of concrete was performed and it resulted in a more durable concrete with replacement of PS balls at 40% and 100% as fine aggregates. These two specific values were considered as optimum replacement is 40% and also the maximum possible replacement is 100%. Scanning electron microscope (SEM) analysis was done and it was found that the PS balls in concrete were unaffected and with optimum percentage of PS balls as fine aggregates in concrete resulted in good strength and less cracks. Hence, it is possible to produce good workable concrete with low water to cement ratio and higher strength concrete by incorporating PS balls.

• Journal of the Korean Regional Science Association
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• v.37 no.4
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• pp.21-32
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• 2021

This study analyzed investment effects for Practical Field Studies conducted by the KOPIA (Korea Program on International Agriculture) centers, which are part of the ODA project operated by the Rural Development Administration. Focusing on the productivity and effectiveness factors of each project, a questionnaire survey was sent to each KOPIA center associated with each project. The results demonstrated the production and profitability of farms participating in the pilot project were significantly improved compared to those of farms that did not participate in the project. Also, in the satisfaction results of taste, nutrition, and freshness, the participating firms could significantly improve them when being compared to those of non-participating farms. It is highly expected to contribute to improving the operational effectiveness of Practical Field Projects conducted in Africa based on the results of each project's performance and economic feasibility. This study also can lead to a change in the social perception of ODA projects by raising people's awareness of ODA projects.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.2
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• pp.115-126
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• 2021

Strategic Environmental Impact Assessment (SEA) is a decision-making process taking into account the environmental impact, economic and social impact of policies, plans, and programs at the higher stage prior to the project plan for promoting sustainable development. In this study, we analyzed the process and criteria for selecting appropriate alternatives when establishing development plan in SEA. First, the criteria for estimating changes in ecosystem services following the implementation of development project of industrial complex were presented. Second, alternative evaluations were conducted through an analysis of ecosystem service scenarios to explore suitable alternatives in Anseong. As a result, the environmental quality of selected area as the existing project site deteriorated according to the implementation of the project, and the dimensional reduction technique confirmed that the change in ecosystem service factors in project area was the optimal location. In addition, the results of the scenario assessment to explore suitable alternatives in Anseong City showed that the existing site had large capacity in terms of water quality control services (scenario 1), scenario 2 in terms of preconditioning services, and scenario 3 in terms of water supply services. The guidance of Ecosystem service assessment is expected to be available in decision-making of large-scale strategies (e.g., SEA) and projects by presenting more quantitative criteria for determining the adequacy and location feasibility of development plans and policy plans. This is expected to require various support, including legislation and revision of related laws, believed to be supported by advanced research.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.1
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• pp.95-111
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• 2019

This study is the 2nd report following "A Study on the Characteristics of Material in the Korean Up-cycling Fashion Brands (Part I)" that handled the development of upcycling props using the characteristics of upcycling material. The 2nd report analyzed product types and materials focusing on 21 foreign upcycling fashion brands. It analyzed the characteristics of upcycling fashion materials using the case analysis of coffee bean bag and waste denim based on external characteristics and internal characteristics. We then classified the external characteristics into environment/economic feasibility and availability/mixture and the internal characteristics into historicality/story and originality/scarcity. Five bags were designed and produced for the actual commercialization of fashion products based on such characteristics of materials, with the use of coffee bean bags and waste denim as upcycling materials. This study is differentiated from existing research by its suggestions for the utilization of fashion product upcycling coffee bean bags and waste denim. Also, upcycling fashion products could be competitive products in eco-friendliness and originality that can be a driving force for the sustainable development of fashion industry through the differentiation of existing fashion products.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1381-1390
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• 2021

Smart grid is a representative convergence new technology in the era of the 4th industry revolution that deals with three broad security areas consisting of control system, the power grid, and the consumer. As it is a convergence new technology of the 4th industrial society, it is true that it can have a positive effect on the country's technological development, growth engine, and economic feasibility in the future. However, since the smart grid is expected to cause enormous damage in the event of a security accident, energy-related organizations must prepare various security measures to predict and respond to the latest security incidents. In this paper, the current status of domestic and foreign smart grids, trends in security standards, vulnerabilities and threats, and prospects for smart grid security technologies are to be considered.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.2
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• pp.57-66
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• 2018

When developing projects to build facilities to be shared by both military bases and surrounding communities, strategies are needed to achieve two objectives: 1) minimize missteps and opposition from local communities in the process of developing and implementing such projects, and 2) promote cost-benefit optimization and user-satisfaction. With aim of promoting co-operation and co-existence between military bases and adjust communities, this research proposes esthetical factors to be considered in conceiving civil-military sharing facilities. It seeks experts' opinions on the development of civil-military sharing facilities, and examines critical factors (economic feasibility, security, and satisfaction, etc.) for project development as well as building types suitable for shared-use between military bases and local residents. It then establishes a method to prioritize facility-type and narrow down design factors (considerations and restrictions) in project development by applying quantitative analysis. The methodological approach of the research employs the Delphi survey method to quantitatively analyze qualitative information drawn from experts' opinions. At the first round of the survey, facility types, items for consideration and restrictions are drawn, and then at the second round of the survey, criticality of each item is analyzed. Finally, it reaches a conclusion on suitability of facility types for civil-military sharing facilities, and selects project considerations and restrictions when developing this kind of project.

• Journal of Hydrogen and New Energy
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• v.32 no.6
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• pp.573-584
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• 2021

Hydrogen is evaluated as one of the new energy sources that can overcome the limitations and pollution problems of conventional fossil fuels. Although hydrogen is CO₂-free, attention is required in NO_x emission and flame stability in order to use hydrogen in existing gas fuel system. However, use of electric grids is an unrealistic strategy for decarbonization for residential and commercial heating. Instead, use of H₂ that utilizes city gas grid is suggested as a reasonable alternative in terms of compatibility with existing systems, economic feasibility, and accessibility. In this study, the thermal efficiency and NO_x performance of the boiler according to the H₂ mixture ratio and vapor humidified ratio are reviewed for a humidified NG-H₂ boiler that vapor humidity to combustion air. Mixed fuel with H₂ (20%) is almost similar to NG in terms of efficiency, flame temperature, and pollution performance. Thus, it is expected to be directly compatible with the existing NG system. If the exhaust temperature of the H₂ boiler is lowered to around 60℃ at a humidified ratio of 15-20%, the NO_x emission concentration can be suppressed to about 5-10 ppm. The level of efficiency reaches 87% of the rated load efficiency, which is equivalent to the highest grade achievable.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.629-640
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• 2021

According to statistics from the Ministry of Land, Infrastructure and Transport in 2018, approximately 37% of residential buildings in Korea need to be reconstructed. Due to the rapid growth of the demolition industry, many side effects such as environmental destruction and safety accidents are becoming a problem in the demolition of existing buildings. This study proposes a decision-making process for selecting the most suitable dismantling method for field application by comprehensively considering safety, economic feasibility, and environmental characteristics. In particular, field applicability is evaluated by evaluating risk factors for the selected method. To this end, this study proposes the TOPSIS method for the selection of the dismantling method using the QFD development concept, and the FMEA method as a continuous development process of the selected method.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.250-256
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• 2009

This paper presents a robotic tower-crane system using encoder and gyroscope sensors as path tracking devices. Tower crane work is often associated with falling accidents and industrial disasters. Such problems often incur a loss of time and money for the contractor. For this reason, many studies have been done on an automatic tower crane. As a part of 5-year 23-million-dollar research project in Korea, we are developing a robotic tower crane which aims to improve the safety level and productivity. We selected a luffing tower crane, which is commonly used in urban construction projects today, as a platform for the robotic tower crane system. This system comprises two modules: the automated path planning module and the path tracking module. The automated path planning system uses the 3D Cartesian coordinates. When the robotic tower crane lifts construction material, the algorithm creates a line, which represents a lifting path, in virtual space. This algorithm seeks and generates the best route to lift construction material while avoiding known obstacles from real construction site. The path tracking system detects the location of a lifted material in terms of the 3D coordinate values using various types of sensors including adopts encoder and gyroscope sensors. We are testing various sensors as a candidate for the path tracking device. This specific study focuses on how to employ encoder and gyroscope sensors in the robotic crane These sensors measure a movement and rotary motion of the robotic tower crane. Finally, the movement of the robotic tower crane is displayed in a virtual space that synthesizes the data from two modules: the automatically planned path and the tracked paths. We are currently field-testing the feasibility of the proposed system using an actual tower crane. In the next step, the robotic tower crane will be applied to actual construction sites with a following analysis of the crane's productivity in order to ascertain its economic efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.324-327
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• 2022

Crack inspection of aged structures is mostly conducted by inspectors using surveying tools on site and visually inspecting them. This method greatly depends on professional worker, and consumes a lot of time and money. An artificial intelligence image classification algorithm is used to make reliable and objective judgments. Since 2018, image augmentation techniques have been used in the image pre-processing stage as they lead to high performance improvement. In this study, an analysis algorithm for cracks in concrete structures was developed using image augmentation techniques, in which the accuracy and speed according to the augmentation ratio were compared and measured for optimization. As a result, it was found that 8 times of image augmentation was appropriate when the accuracy was improved and economic feasibility was taken into account.