• Economic and Environmental Geology
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• v.53 no.6
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• pp.771-779
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• 2020

This study was performed to develop a priority list for post-managements of leachates from 64 mine waste dump sites in Korea. For this, leachate quality, leachate quantity, and other factors were considered as evaluation criteria and the weights of 10 subfactors were calculated using Analytic Hierarchical Process (AHP) based on a survey from 20 experts in the field of mining environment. Calculated weights were 0.769, 0.147 and 0.084 for leachate quality, leachate quantity, and others, respectively, indicating that experts consider leachate quality as most important. Based on this approach, we classified the 64 mine waste dump sites into five grades from Grade I to Grade V. Ten were classified as Grade I, 1 as Grade II, 1 as Grade III, 33 as Grade IV, and 19 as Grade V.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.53-57
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• 1998

In order to investigate the effects of the variables during the stamping process upon the side wall curl behavior, experiments and finite element analyses were done using a 90 degree draw-bending test. The variables considered were the die radius, the forming speed, the restraint force, the lubrication and the sheet grade. The experiments and simulation conditions were selected according to the design of experiment (DOE) approach. The effects of the restraint force, the lubrication and the forming speed were the same for both high strength and mild steels, but the effects of the die radius on the side wall curl were dependent on the magnitude of the die radius and the sheet grade. A straight side wall was observed for both high strength and mild steels when the die radius was about 2∼3 times of the sheet thickness. It was recommended that the restraint force, the forming speed and the friction be increased in order to reduce the side wall curl.

• The Mathematical Education
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• v.43 no.1
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• pp.70-85
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• 2004

Comparing to the other subject, hierarchy among mathematical contents is strong from the perspective of knowledge order as grades go up. That is, the knowledge that students already have learned, are learning and will learn are closed related from grade to grade. We expect students to be proactive and creative in studying mathematics, which is the goal of 21th century, analyzing their. knowledge structure based on the hierarchy of knowledge through assessment. Especially, using computer system we provide students with substantial feedback for the assessment as well as objective validity is increased along with speedy and exact process in a bid to help students' mathematical understanding grow. This paper seeks to analyze the assessment data by applying knowledge spaces to computer system and develops efficient methods based on the analyzed results, to diagram each student's knowledge structure.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.581-590
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• 2013

A research was performed for zero discharge system of waste water which is produced from energy recovery process of waste and biomass. Leachate and all kinds of waste water should be separated and integrated into three categories in addition to converting existing leachate treatment facility into waste water treatment facility as well as introducing a management system of reverse osmosis membrane facility and bioreactor landfill. Following these conditions to better water treatment process, it was likely to produce over 3,000 tons of low-grade recycling water and 2,000 tons of high-grade recycling water per day when zero discharge system of waste water is applied starting from 2016. Economical efficiency was also surveyed in total treatment fee. Present system costs 18,129 million won per year, and suggested zero discharge system would cost 15,789 million won per year.

• Transactions of Materials Processing
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• v.30 no.5
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• pp.236-241
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• 2021

This study describes the cold stamping process design procedure to secure the formability and dimensional accuracy of the automotive structural component fabricated by 1.5GPa grade ultra-high strength steel sheet. The target product is selected as the front side rear lower member which is the most important energy absorption part in the frontal impact condition. To secure the product quality, an intermediate product shape is added while considering the low elongation and high strength characteristics of 1470Mart. The sequential optimization procedure of the intermediate product shape, the fine dimensional quality is then achieved without any crack or wrinkling. The cold stamping method with ultra-high strength steel sheets is validated by conducting the die tryout of the front side rear lower member.

• Resources Recycling
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• v.28 no.3
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• pp.21-25
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• 2019

The utilization of incineration ash from municipal waste must be promoted to solve the social problem on the shortage of final disposal site. In this research, metals should be recovered to avoid the damage of the crushing machine during the utilization of incineration ash in cement industry. In fact, incineration bottom ash from municipal waste contains iron in 3-5%. Nonferrous metal and stainless steel in 1% is also included. The research and development on the physical recovery process was performed not only to remove the metals but also to recover high grade products. Metals were separated from incineration ash in Maruya Co. Ltd.. In fact, iron scrap recovered by magnetic separation can be selled. After that, mixed metal was separated from incineration ash using screen. In this research, mixed metal tried to divided copper, aluminum, brass and stainless steel using drum type magnetic separation, eddy current separation and high magnetic separation. As a result, recovered iron had an 80% for the grade. Aluminum was recovered by eddy current separation without copper and brass.

• East Asian mathematical journal
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• v.37 no.2
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• pp.149-167
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• 2021

The six core competencies included in the mathematics curriculum revised in 2015 are problem solving, reasoning, communication, attitude and practice, creativity and convergence, information processing. In particular, the reasoning is very important for students' enhancing much higher mathematical thinking. Based on this competency, this study selected the four elements of investigation and fact guess, justification, the logical performance of mathematical content and process, reflection of reasoning process, And also this study selected the domain of function which is comprised of the content of the coordinate plane, the graph, proportionality in the seventh grade mathematics textbook. By the subject of the ten kinds of textbook, this study examined how the four elements of the reasoning competency were shown in each textbook.

• Journal of Elementary Mathematics Education in Korea
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• v.24 no.1
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• pp.129-149
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• 2020

This study reports the results of analyzing the learning opportunities about the plane figures provided by the first and second grade mathematics textbooks. The plane figures that students learn during this period are important in that it serves as the basis for the later geometric education. With assumptions that mathematics learning is related to the problem of meaning and that meaning-related activity can be viewed as a symbolic activity, it adopts and uses the perspectives and tools of semiotics to analyze the learning opportunities provided by the mathematics textbook. The analysis of the semiotic process of the textbook activities revealed the significance of learning opportunities and helped to distinguish the seemingly similar learning opportunities. Based on the results of the analysis, I discussed the link between learning opportunities provided by grade 1 and grade 2 mathematics textbooks. Finally, the paper concludes with suggestions and conclusions and suggestions for further research.

• Journal of Korean Clinical Nursing Research
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• v.21 no.2
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• pp.154-168
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• 2015

Purpose: This study aimed to adapt the previously developed, high-quality oral care guideline for the usage in clinical settings in Korea. Methods: Guideline adaptation process was undertaken according to the guideline adaptation manual version 2.0 developed by National Evidence-based Healthcare Collaborating Agency (Kim, et al., 2011) and the standardized methodology for nursing practice guideline adaptation (Gu, et al. 2012). Results: The adapted oral care guideline was consisted of 10 domains and 85 recommendations. The number of recommendations in each domain were: 4 general issues, 2 oral care indications, 10 oral assessment 16 general oral care, 15 oral care for critically ill, 15 oral care for cancer patients, 14 oral care for cancer patients withoral complications, 5 oral careeducation, 2 oral care referral, and 2 documentation and report. Ten point six percent of the recommendations were rated as grade A, 20.0% as grade B grade, and more than half (69.4%) were rated as grade C. Conclusion: The adapted oral care practice guideline is expected to included the evidence-based practice guidelines as fundamentalss of nursing practice. Dissemination of the developed guideline nationwide would contribute improving the efficiency of oral care practice.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.16-25
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• 2002