• Journal of the Korean School Mathematics Society
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• v.22 no.1
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• pp.1-21
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• 2019

Mathematics is one of the subjects in which learners seriously experience under-achievements in school education. Middle school level mathematics especially plays such a role as a bridge between elementary level informal mathematics and high school level formal mathematics that learners' under-achievements in the middle school level mathematics may yield more serious under-achievements later. Therefore it is crucial to prevent learners' later under-achievements that we analyze the status of under achievements including analysing various under-achievers' errors in the middle school level mathematics. From this point of view, we analysed errors of mathematics under-achievers in understanding the concept of the square root of positive numbers and related calculations in this paper. As the results of our research, we found some unexpected errors of 'some mathematics under-achievers regarding the mathematical symbol ${\surd}$ of square root as a parenthesis ( ), and others interpret $x=-2{\pm}{\sqrt{10}}$ as x=-2 or ${\pm}{\sqrt{10}}$.' that suggest the necessity of more various and in-depth discussions and researches of analysis on learners' errors and misconceptions in all areas of school mathematics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.2
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• pp.160-168
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• 2019

In this study, we propose a verification method for a planar-phased array radar system using a near-field beam focusing(NFBF) test method. We then confirmed the validity of the results. The proposed method can be used to verify a radar system in the near-field range of twice the antenna aperture size, and this is done in the same manner as the field system performance test conducted in a non-outdoor electromagnetic anechoic chamber. The test configuration and procedure for verifying the NFBF using near-field energies were reviewed. In addition, the phase compensation values of additional individual channels were quantified through mathematical verification of the beam-steered NFBF test. Based on a theoretical verification, the actual NFBF test was performed and the validity of the test method was confirmed through comparison with ideal analytical results.

• Education of Primary School Mathematics
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• v.24 no.4
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• pp.233-246
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• 2021

Two-dimensional shapes have a great influence on elementary school students' learning and are closely related to other content areas. Therefore, in this study, The Teaching and Learning Elements that should be taught in two-dimensional shapes were extracted from the literature. It also was analyzed that revised mathematics textbooks in the year 2015 were properly implemented with the teaching and learning elements. As a result of the analysis, in the case of Understanding The Concept, the activities in the textbooks are not able to recognize 2-D shapes which are focusing on shapes of the actual object. In the case of Classifying two-dimensional shapes according to the Criteria, the classification criteria were presented differently from what was learned in the previous course. In the aspect of Applying the Concept, the activities in order to Discuss two-dimensional shapes were not sufficient. Lastly, in view of the fact the 2015 revised curriculum is not considered with the relationship between two-dimensional shapes. For that reason, the following Knowing Relationships parts are insufficiently presented; Understanding the Relationship Between shapes through Definitions and Properties, Identifying the relationship between shapes throughout classification activities, and Discussing the relationship between shapes. Based on the analysis result of two-dimensional shapes, it is suggested that the finding of this research helps to enlarge the teaching methodology of triangles and provide educational perspectives for development in other shape areas.

• Clean Technology
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• v.27 no.3
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• pp.269-274
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• 2021

Bioenergy is generally considered to be one of the options for pursuing carbon neutrality. However, for a period of time, combustion of harvested plant biomass inevitably causes more carbon dioxide in the atmosphere than combustion of fossil fuels. This paper proposes a method that predicts and minimizes the total amount and payback period of this carbon debt. As a case study, a carbon cycle impact assessment was performed for immediate switching of the currently used fossil fuels to biomass. This work points out a fundamental vulnerability in the concept of carbon neutrality. As an action plan for the sustainability of bioenergy, formulas for afforestation proportional to the decrease in the forest area and surplus harvest proportional to the increase in the forest mass are proposed. The results of optimization indicate that the carbon debt payback period is about 70 years, and the carbon dioxide in the atmosphere increases by more than 50% at a maximum and 3% at a steady state. These are theoretically predicted best results, which are expected to be worse in reality. Therefore, biomass is not truly carbon neutral, and it is inappropriate as an energy source alternative to fossil fuels. The method proposed in this work is expected to be able to contribute to the approach to carbon neutrality by minimizing present and future carbon debt of the bioenergy that is already in use.

• Journal of the Korean School Mathematics Society
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• v.24 no.1
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• pp.59-81
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• 2021

This study aimed to investigate how the learners' mathematics learning processes change with repeatedly reading mathematical text. As a way to teach and learn mathematics, we also wanted to examine the effect of repeated reading and to explore the implications for a more efficient teaching and learning strategy. To help us with this study, we mainly used eye tracking and heart rate (HR) measurement. There were four cycles in a cycle of repeated reading, and the number of repeated readings for all cycles was fixed to three times. Eight prospective mathematics teachers in the Department of Mathematics Education of a National University in South Korea participated. Data were analyzed in five aspects: (1) the total reading time per round, the total reading time per slide; (2) the change trends of total reading time per round and slide; (3) the order of slides read; (4) the change trends of HR per round. We found that most participants read in a similar pattern in the first reading, but the second and third reading patterns appeared more diverse for each learner. Also, the first reading required the most time regardless of the repeat cycle, and the time it took to repeatedly read afterward varied depending on the individual. Based on the findings of this study, the most primary conclusion is that self-directed mathematics learning by using repeated reading is effective regardless of cycle. In addition, we suggested four strategies to improve the efficiency of this teaching and learning method.

• Journal of the Korean School Mathematics Society
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• v.24 no.1
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• pp.151-172
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• 2021

In this study, I investigated prospective mathematics teachers' perceptions of activities using Wax-paper, a hands-on material (manipulatives), and GeoGebra, a technological tool, in teaching quadratic curves. Twenty prospective mathematics teachers in the Mathematics Education Department of a local university participated in a survey on their perception of the use of hands-on materials and technological tools in teaching quadratic curves. According to the results of this study, prospective mathematics teachers generally preferred the use of technological tools for learning and teaching quadratic curves. Additionally, mathematics teachers thought that the tool helped students develop intuitive thinking through visualizing quadratic curves, enabling the exploration of various mathematical properties, assisting the comprehension of various concepts, and increasing students' interest levels. However, they were concerned about the immature use of technological tools by students or teachers, and recognized that the advantages and disadvantages of using hands-on material and technological tools were complementary. Based on these findings, it is suggested that hands-on material and technological tools should be used complementally in mathematics classes, and the development and dissemination of class materials that are not affected by students' or teachers' ability to use technological tools is important.

• Education of Primary School Mathematics
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• v.24 no.2
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• pp.71-81
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• 2021

In this study, I investigate the relationship between mathematics anxiety and mathematics teacher anxiety of elementary school teachers with integrated method. As a result of statistical analysis of the survey of 256 elementary school teachers, there was a statistically significant positive correlation between the two factors (r = .630, p <.05). The analysis show that teaching experience and degree may affect mathematics anxiety and teaching experience, degree, and teacher qualification may affect mathematics teaching anxiety. Subsequently I conduct a qualitative study focusing on interviews with 20 elementary school teachers. As a result of the analysis, I confirm that even if the mathematics anxiety is low, mathematics teaching anxiety may occur due to the teaching environment. As a result of the quantitative and qualitative analysis of this study, Korean elementary school teachers' mathematics anxiety and mathematics teaching anxiety might be regarded as separate factors. From the result of the study, I suggest that mathematics anxiety and mathematics teaching anxiety of elementary school teachers, each emotional state might be considered as independent emotional status. The implication of the study indicate that independent methods might be developed in order to prevent and treat mathematics anxiety and mathematics teaching anxiety in elementary school teachers.

• Journal of the Korean earth science society
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• v.40 no.5
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• pp.518-537
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• 2019

This study examined the implications of a place-based earth science program integrated with Mathematics. 11 pre-service earth science teachers and 22 middle school students participated in the service education activities of earth science for 30 hours focusing on the measurement of the earth's size through earth science experiments as part of the middle school curriculum. In order to minimize errors that may occur during the earth's size measurement experiments using Eratosthenes's shadows length method of the ancient Greek era, the actual data were collected after triangulation ratios were conducted in the locations of two middle schools: one in remote metropolitan and the other in rural area. The two schools' students shared the final estimate result. Through this process, they learned the mathematical method to express the actual data effectively. Participants, experienced the importance and difficulty of the repetitive and accurate data acquisition process, and also discussed the causes of errors included in the final results. It implies that a Place-Based Earth Science Program activity can contribute to students' increased-understanding of the characteristics of earth science inquiry and to developing their problem solving skills, thinking ability, and communication skills as well, which are commonly emphasized in science and mathematics in the 2015 reunion curriculum. It is expected that a place-based science program can provide a foundation for developing an integrated curriculum of mathematics and science.

• Education of Primary School Mathematics
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• v.22 no.4
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• pp.261-280
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• 2019

This study is a qualitative study on the case of teaching mathematics between parents and children. 12 lesson units were applied to the 5th grade elementary school child for the first semester, 2019. The purpose of this study was to identify conceptual understanding in the area, the types of problems that child felt difficult during the learning and parents' advantages and difficulties in this setting. For this study, video recording and voice recording were collected for each lesson class. The concept of the area was recognized correctly, the awareness of reconstruction became clear, and the concept of partitioning, unit iteration and structuring an array was more clearly rebuilt. He showed difficulty in conversion between units of the area, in displaying height of the shape whose height is displayed outside and drawing type of figure with same area after the value of the area was offered. In the learning situation of parents and children, parents who are researchers have the advantage of being able to customize up to their children and being free from time and cost constraints. There were difficulties in controlling negative emotion toward the child, determining the level of the children, distribution the class time and deciding the degree of intervention. Furthermore, research on parenting and child-to-parent teaching in mathematics is recommended.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.43-52
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• 2020

As the membrane gas separation technology grows, various models were developed by numerous researchers to describe the separation process. In this work, the counter-current model was compared thoroughly with experimental data. Experimentally, hollow fiber membrane using CA module was prepared for the separation of biogas. The pure gas permeation properties of membrane module for methane, nitrogen, oxygen, and carbon dioxide were measured. The permeance of CO2 and CH4 were 25.82 GPU and 0.65 GPU, respectively. The high CO2/CH4 selectivity of 39.7 was obtained. the separation test for three different simulated mixed gases were carried out after pure gas test, and the gas concentration of the permeate at various stage-cut were measured from CA membrane module. Results showed that the experimental data agreed with the numerical simulation. A mathematical model has implemented in this study for the separation of biogas using a membrane module. The finite difference method (FDM) is applied to calculate the membrane biogas separation behaviors. Futhermore, the counter-current model can be considered as a convenient model for biogas separation process.