• Research in Mathematical Education
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• v.21 no.1
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• pp.35-46
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• 2018

In this perspective paper, we present seven elements of the appropriate educator mindset for teaching in the constructivist elementary mathematics classroom. The elements include supporting students as they construct their own understanding, eliminating deficit view of slow learners, setting new understanding and growth as the learning objective, providing opportunities to co-construct meaning with peers, using student contributions as the source of curricular material, encouraging all students to participate in learning, and providing instruction not bounded by time. In our struggles to provide authentic, inclusive elementary classrooms, we hope that our discussion of the educator mindset can increase discourse on constructivism from philosophy to practice in the community of mathematics education and policy makers.

• Bulletin of the Korean Mathematical Society
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• v.56 no.3
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• pp.569-583
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• 2019

Given a graph G, the Motzkin and Straus formulation of the maximum clique problem is the quadratic program (QP) formed from the adjacent matrix of the graph G over the standard simplex. It is well-known that the global optimum value of this QP (called Lagrangian) corresponds to the clique number of a graph. It is useful in practice if similar results hold for hypergraphs. In this paper, we attempt to explore the relationship between the Lagrangian of a hypergraph and the order of its maximum cliques when the number of edges is in a certain range. Specifically, we obtain upper bounds for the Lagrangian of a hypergraph when the number of edges is in a certain range. These results further support a conjecture introduced by Y. Peng and C. Zhao (2012) and extend a result of J. Talbot (2002). We also establish an upper bound of the clique number in terms of Lagrangians for hypergraphs.

• Research in Mathematical Education
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• v.22 no.3
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• pp.223-243
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• 2019

Researchers have been attending to the potential of curriculum materials as resources for professional development. In order for a curriculum material to fulfil such purpose, curriculum authors should intentionally attend to educativeness of the material. A feature of educative material is that its voice speaks to teachers. In this study, I explore educativeness of Algebra teacher guides by attending to their voice. In particular, I focused on the use of pronouns, modality, and imperatives. Findings indicate that some teacher guides have more educative voice than the others and that the amount each guide talk to teachers were less than sufficient. Implications for future research and practice are discussed.

• Research in Mathematical Education
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• v.25 no.1
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• pp.21-43
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• 2022

Investigating the relationship between intrinsic and extrinsic motivation and their effects on affective mathematics engagement in a cultural context is critical for determining which types of motivation promote affective mathematics engagement and the relationship with cultural affordance. The investigation in the current study is comprised of two dependent studies. The results from Phase 1 indicate that attitude and emotion are better explained by extrinsic motivation, while self-acknowledgment and value are better explained by intrinsic motivation. The results of Phase 2 indicate that the Korean sample has greater extrinsic motivation, attitude, and emotion, while the U.S. sample has greater intrinsic motivation, self-acknowledgment, and value. The key outcome for this research is that disentangling cultural affordance from the emotional and cognitive structures is impossible.

• East Asian mathematical journal
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• v.39 no.2
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• pp.183-198
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• 2023

Classroom observation instruments are often used to evaluate teachers' instructional practices and provide feedback to inform interventions or research studies, or professional development efforts. While designed as research tools, many classroom observation instruments can provide important information to support teachers' learning and instructional change by providing a focus for formative assessment or self-evaluation of practice. In this paper, we review two classroom observation tools and the protocols for their use with an implementation example for one of the tools. These tools are more foreign to the field compared to others but have features that might serve as affordances in relation to the purposes of a specific investigation.

• East Asian mathematical journal
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• v.39 no.2
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• pp.229-250
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• 2023

The purpose of this study is to investigate the impact of project learning using chatbots on artificial intelligence literacy. The subjects of the study were a total of 41 students from 1st to 3rd grade of general high school in Gyeonggi-do. Classes were held after school for a total of 6 hours, and the contents of the classes consisted of the concept and characteristics of artificial intelligence, the concept and expression of knowledge, OBT application for Kakao i open builder, guidance on how to create chatbots, and chatbot production practice. As a result of the pre- and post-test of the experimental group, the quantitative value of artificial intelligence literacy increased in all three grades. In the case of second-year students who set up a comparison group, when compared with the results of the comparison group, there was a significant positive effect on the AI literacy result, and female students were found to be more effective than male students.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1565-1577
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• 2016

For grid-connected LCL-filtered inverters, dual-loop current control with an inner-loop active damping (AD) based on capacitor current feedback is generally used for the sake of current quality. However, existing studies on capacitor current feedback AD with a control delay do not reveal the mathematical relation among the dual-loop stability, capacitor current feedback factor, delay time and LCL parameters. The robustness was not investigated through mathematical derivations. Thus, this paper aims to provide a systematic study of dual-loop current control in a digitally-controlled inverter. At first, the stable region of the inner-loop AD is derived. Then, the dual-loop stability and robustness are analyzed by mathematical derivations when the inner-loop AD is stable and unstable. Robust design principles for the inner-loop AD feedback factor and the outer-loop current controller are derived. Most importantly, ensuring the stability of the inner-loop AD is critical for achieving high robustness against a large grid impedance. Then, several improved approaches are proposed and synthesized. The limitations and benefits of all of the approaches are identified to help engineers apply capacitor current feedback AD in practice.

• The Mathematical Education
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• v.53 no.3
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• pp.357-381
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• 2014

This study analyzed the cases of three teacher communities participating in an innovative professional development program and clarified the characteristics and the process of lessons for mathematics-oriented convergence that were developed and applied during the program. Each of the teacher communities designed and implemented lessons according to the context of each community and the concept of lessons for mathematics-oriented convergence were developed and refined. The lessons developed by the three teacher communities were characterized as convergence problem posing lessons using technology, convergence of various subject content focused on mathematical concepts through team teaching, and convergence lessons according to students' achievement levels. The program contributed to teacher community activities by proving sustainable professional development in the area of convergence education, a connection between the content of their professional development and the context of the field, and opportunities for active participation in the process of developing and implementing the convergence lessons.

• Computers and Concrete
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• v.4 no.1
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• pp.1-18
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• 2007

Over the past decades, an enormous amount of effort has been expended in laboratory and field studies on concrete durability estimation. The results of this research are still either widely scattered in the journal literature or mentioned briefly in the standard textbooks. Moreover, the theoretical approaches of deterioration mechanisms with a predictive character are limited to some complicated mathematical models not widespread in practice. A significant step forward could be the development of appropriate software for computer-based estimation of concrete service life, including reliable mathematical models and adequate experimental data. In the present work, the basis for the development of a computer estimation of the concrete service life is presented. After the definition of concrete mix design and structure characteristics, as well as the consideration regarding the environmental conditions where the structure will be found, the concrete service life can be reliably predicted using fundamental mathematical models that simulate the deterioration mechanisms. The prediction is focused on the basic deterioration phenomena of reinforced concrete, such as carbonation and chloride penetration, that initiate the reinforcing bars corrosion. Aspects on concrete strength and the production cost are also considered. Field observations and data collection from existing structures are compared with predictions of service life using the above model. A first attempt to develop a database of service lives of different types of reinforced concrete structure exposed to varying environments is finally included.

• Journal of Educational Research in Mathematics
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• v.12 no.4
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• pp.473-491
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• 2002

This article analyzes mathematics education from dialectical materialism acknowledging the objectivity of knowledge. The thesis that knowledge is objective advances to the recognition that knowledge will be internalized, and an idea of zone of proximal development(ZPD) is established as a practice program of internalization. The lower side of ZPD, i.e. the early stage of internalization takes imitation in a large portion. And in the process of internalization the mediational means play an important role. Hereupon the role of mathematics teacher, the object of imitation, stands out significantly. In this article, treating the contents of study as follows, I make manifest that teaching and learning in mathematics classroom are united dialectically: I hope to findout the method of teaching-learning to mathematical knowledge from the point of view that mathematical knowledge is objective; I look into how analysis into units, as the analytical method of Vygotsky, has been developed from the side of mathematical teaching-learning; I discuss the significance of mediational means to play a key role in attaining the internalization in connection with ZPD and re-illuminate imitation. Based on them, I propose how the role of mathematics teachers, and the principle of organization to mathematics textbook should be.