• School Mathematics
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• v.6 no.1
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• pp.59-90
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• 2004

This study has been established with two purposes. The first one is to development the learning-teaching model for enhancing students' creative proof capacities in the domain of demonstrative geometry as subject content. The second one is to aim at experimentally testing its effectiveness. First, we develop the learning-teaching model for enhancing students' proof capacities. This model is named the generative-convergent model based instruction. It consists of the following components: warming-up activities, generative activities, convergent activities, reflective discussion, other high quality resources etc. Second, to investigate the effects of the generative-convergent model based instruction, 160 8th-grade students are selected and are assigned to experimental and control groups. We focused that the generative-convergent model based instruction would be more effective than the traditional teaching method for improving middle school students' proof-writing capacities and error remediation. In conclusion, the generative-convergent model based instruction would be useful for improving middle grade students' proof-writing capacities. We suggest the following: first, it is required to refine the generative-convergent model for enhancing proof-problem solving capacities; second, it is also required to develop teaching materials in the generative-convergent model based instruction.

• Journal of The Korean Association For Science Education
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• v.37 no.4
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• pp.565-575
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• 2017

This study analyzes the epistemic considerations and the argumentation level revealed in the discourse of the key concept of natural selection for science-gifted elementary students. The paper analyzes and discusses the results of a three-student focus group, drawn from a cohort of twenty gifted sixth-grade elementary students. Nature, generality, justification, and audience were used to analyze epistemic consideration. Learning progression in scientific argumentation including argument construction and critique was used to analyze students' scientific argumentation level. The findings are as follows: First, Epistemic considerations in discourse varied between key concepts of natural selection discussed. The nature aspect of epistemic considerations is highly expressed in the discourse for all natural selection key concepts. But the level of generality, justification and audience was high or low, and the level was not revealed in the discourse. In the heredity of variation, which is highly expressed in terms of generality of knowledge, the linkage with various phenomena against the acquired character generated a variety of ideas. These ideas were used to facilitate engagement in argumentation, so that all three students showed the level of argumentation of suggestions of counter-critique. Second, students tried to explain the process of speciation by using concepts that were high in practical epistemic considerations level when explaining the concept of speciation, which is the final natural selection key concept. Conversely, the concept of low level of epistemic considerations was not included as an explanation factor. The results of this study suggest that students need to analyze specific factors to understand why epistemological decisions are made by students and how epistemological resources are used according to context through various epistemological resources. Analysis of various factors influencing epistemological decisions can be a mediator of the instructor who can improve the quality and level of the argumentation.

• Journal of Elementary Mathematics Education in Korea
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• v.24 no.1
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• pp.169-186
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• 2020

The purpose of this study is to find new material for developing teaching and learning materials for the gifted class of elementary school students by using the rotatable tangram made by modifying the traditional tangram. Rotatable tangram can be justified by gifted students through mathematical communication. However, even gifted class students have some limitations in finding and justifying triangles and rectangles of all sizes unless they go through the 'symbolization' stage at the elementary school level. Therefore, students who need an inquiry process for letters and symbols need to provide supplementary learning materials and additional questions. It is expected that the material of rotatable tangram for the development of teaching and learning materials for elementary school gifted students will contribute to the development of mathematical reasoning and mathematical communication ability.

• Journal of Gifted/Talented Education
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• v.27 no.1
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• pp.37-57
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• 2017

In terms of making more various geometrical figures than existing Tangram, Sphinx Puzzle has been used as a material for the gifted education. The main research subject of this paper is to verify how many convex polygons can be made by all pieces of a Sphinx Puzzle. There are several previous researches which dealt with this research subject, but they did not account for the clear reasons on the elementary level. In this thesis, I suggest using unit area and minimum area which can be proved on the elementary levels to account for this research subject. Also, I composed the program for the mathematically gifted elementary students, regarding the subject. I figured out whether they can make the mathematical justifications. I applied this program for three 6th grade students who are in the gifted class of the G district office of education. As a consequence, I found that it is possible for some mathematically gifted elementary students to justify that the number of convex polygons that can be made by a Sphinx Puzzle is at best 27 on elementary level.

• Journal of the Korean Chemical Society
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• v.44 no.4
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• pp.356-362
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• 2000

Students' protocols obtained from audio/video taping of small cooperative group problem solving processes were analyzed in the aspectsof verbal behaviors. The frequencies of the behaviors were com-pared by students' previous achievement level. Students' involvement in the verbal interaction for each level of students in each small group were also investigated. High-ability students ebility students and medium-or low-ability students.No significant differences were found in the subcategories of 'receiving information' or 'asking'. 0nly 3 small groups among 12 groups studied were found tobe bal-anced in students' involvelment. lnvolvement of medium-ability studentstended to be lower than that of high-and low-abilit students.

• Education of Primary School Mathematics
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• v.27 no.2
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• pp.187-198
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• 2024

The addition and subtraction relationship and the multiplication and division relationship are explicitly dealt with in second and third grade mathematics textbooks. However, these relationships are not discussed anymore in the problem situations and activities in the 4th, 5th, and 6th grade mathematics textbooks. In this study, we investigate the calculation principles of subtraction and division in the elementary school mathematics textbooks. Based on our investigation, we justify the addition and subtraction relationship and the multiplication and division relationship at the level of children's understanding so that we discuss some problem situations and activities where the relationships can be applied to subtraction and division. In addition, we suggest educational implications that can be obtained from children's applying the relationships and the properties of equations to subtraction and division.

• Research in Plant Disease
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• v.16 no.3
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• pp.285-289
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• 2010

The experiments were carried out in fields for two years from 2008 to assess yield losses of squash due to powdery mildew caused by Sphaerotheca fuliginea and to determine its economic thresholds. Powdery mildew disease was first observed in late June, about 50 days after field-transplanting, progressed rapidly during late July to early August, and began to reduce from late August. Powdery mildew severity was negatively correlated with squash yields. A positive correlation was observed between fruit weight and % marketable fruits. A simple linear regression model was obtained as Y=-10.399 X + 6607.5 with $R^2$ = 0.9700 when squash yields (Y) was predicted using powdery mildew severity as an independent variable(X). Spray threshold for maximizing squash yields without economic considerations was estimated as 6.5% in terms of leaf lesion area with powdery mildew. Economic threshold and economic spray threshold able to compensate the costs of fungicide sprays were determined as 21.6% and 17.3% in leaf lesion area, respectively.

• Journal of the Korean School Mathematics Society
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• v.15 no.1
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• pp.53-80
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• 2012

This study was designed to find the characteristics of mathematical errors and discourse in simultaneous equations and inequalities for migrant students from North Korea. 5 sample students participated, who attended in an alternative school for the migrant students from North Korea at the study in Seoul, Korea. A total of 8 lesson units were performed as an extra curriculum activity once a week during the 1st semester, 2011. The results indicated that students showed technical errors, encoding errors, misunderstood symbols, misinterpreted language, and misunderstood Chines characters of Koreans and the discourse levels improved from the zero level to the third level, but the scenes of the third level did not constantly happen. Nevertheless, the components of discourse, explanation & justification, were activated and as a result, evaluation & elaboration increased in ERE pattern on communication.

• Journal of The Korean Association For Science Education
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• v.35 no.3
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• pp.419-429
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• 2015

In this study, we explored students' epistemological framing during scientific argumentation and how interactions among group members influenced group argumentation. Twenty-one gifted science students divided into groups of three or four participated in this study. Students' discussions related to data interpretation concerning the rate of photosynthesis were analyzed. Students' activities were videotaped in groups so the discourse could be transcribed and students' behavioral cues analyzed. Students' epistemological framing has been identified through analysis of their speech and behavioral responses to the anomalous data from the inquiry process. Subsequently, their sources of warrant and group argumentation levels were explored. We found out that group members framed the inquiry in two ways: "understanding phenomena" and "classroom game." Group members whose framing was "understanding phenomena" required other members to justify the anomalous data by examining its validity and reliability, which conclusively demonstrated a high level of argumentation. On the other hand, when group members used "classroom game" to frame their argumentation, they did not recognize the necessity of explaining the anomalous data; rather, these students used simple empirical justification to explain the data, reflecting a low level of argumentation. When students using different epistemological framing disagreed over interpretations of anomalous data throughout the discussion, clashes ensued that resulted in emotional conflict and a lack of discussion. Students' framing shifts were observed during the discussion on which group leaders seemed to have a huge influence. This study lays the foundation for future work on establishing productive framing to prompt scientific argumentation in science classrooms.

• Korean journal of communication and information
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• v.44
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• pp.144-179
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• 2008

This paper explores the formation of global responsibility discourses in the elite US media used in promoting NATO's military interventions in the post-Cold War era. The case study of global responsibility discourses surrounding the Bosnian War (1992-1995) and the Kosovo Conflict (1998-1999) offers an account of the roles of the elite US media in foreign policy. The construction and articulation of global responsibility discourses in the elite US media were closely related to the US government's policy and were formed within the framework of US national interest and domestic responsibility. The cases of military intervention in the post-Cold War period imply that there were more fundamental structure and patterns by which the elite US media approached the 'humanitarian crises': 'benevolent domination' and the subsequent construction of a 'melodramatic national identity' in the war narratives. Presuming that the elite US media's discourse is a primary site for the public for experiencing and understanding distant suffering, this paper concludes that global responsibility discourses within the media may have dangerous ramifications for global democracy because the discourse of responsibility can potentially absorb the creative, progressive energies created by the public's awareness of responsibility on a global scale in order to reinforce the relations of domination.