• Bulletin of the Korean Mathematical Society
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• v.58 no.6
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• pp.1507-1520
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• 2021

Let R be a commutative ring with 1 ≠ 0, n be a positive integer and M be an R-module. In this paper, we introduce the concept of weakly quasi n-absorbing submodule which is a proper generalization of quasi n-absorbing submodule. We define a proper submodule N of M to be a weakly quasi n-absorbing submodule if whenever a ∈ R and x ∈ M with 0 ≠ aⁿ x ∈ N, then aⁿ ∈ (N :_R M) or a^n-1 x ∈ N. We study the basic properties of this notion and establish several characterizations.

• The Pure and Applied Mathematics
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• v.25 no.3
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• pp.203-218
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• 2018

An old result of Whitehead says that the set of derivations of a group with values in a crossed G-module has a natural monoid structure. In this paper we introduce derivation of crossed polymodule and actor crossed polymodules by using Lue's and Norrie's constructions. We prove that the set of derivations of a crossed polygroup has a semihypergroup structure with identity. Then, we consider the polygroup of invertible and reversible elements of it and we obtain actor crossed polymodule.

• Bulletin of the Korean Mathematical Society
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• v.51 no.4
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• pp.1163-1173
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• 2014

Let R be a commutative ring with $1{\neq}0$. In this paper, we introduce the concept of 2-absorbing primary ideal which is a generalization of primary ideal. A proper ideal I of R is called a 2-absorbing primary ideal of R if whenever $a,b,c{\in}R$ and $abc{\in}I$, then $ab{\in}I$ or $ac{\in}\sqrt{I}$ or $bc{\in}\sqrt{I}$. A number of results concerning 2-absorbing primary ideals and examples of 2-absorbing primary ideals are given.

• Research in Mathematical Education
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• v.3 no.1
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• pp.9-21
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• 1999

In mid 1980s, open education arrived in Korea. It was influenced by the educational reforms implemented in American primary schools. Currently, the Ministry of Education is appealing to teachers for their active involvement in educational reform by using open education methodology. Often teachers in Korea complain that they do not know what to do or how to change in order to practice the open education. It is time to review the state of open education in Korea and the United States. This paper contains the following segments: 0) Introduction, 1) Beginning of open education, 2) A brief history of open education in Korea, 3) The current status of open education in the United States, 4) A glance at open mathematics classroom in Korea, 5) Lessons from the review, and 6) Conclusion.

• East Asian mathematical journal
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• v.29 no.2
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• pp.109-135
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• 2013

The purpose of the study was to investigate the reality of middle school mathematics teachers' subject matter knowledge for teaching mathematical conjecture and justification. Data in the study were collected through interviewing nine Chinese and ten Korean middle school mathematics teachers. The teachers responded to the question that was designed in the form of a scenario that presents a teaching task related to a geometrical topic. The teachers' oral responses were audiotaped and transcribed, and their written notes were collected. The results of the study were compared to the analysis of American and Chinese elementary and secondary teachers' responses to the same task in Ball (1988) and Ma (1999). The findings of the study suggested that teachers' approaches to explaining and demonstrating a mathematical topic were significantly influenced by their knowledge of learners and knowledge of the curriculum they teach. One of the practical implications of the study is that teachers should recognize the advantages of learning the conceptual structure of a mathematical topic. It allows the teachers to have the flexibility to come up with meaningful mathematical approaches to teaching the topic, which are comprehensible to the learners whatever the grade levels they teach, rather than rule-based algorithms.

• Journal of the Korean School Mathematics Society
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• v.15 no.1
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• pp.1-25
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• 2012

The purpose of this study is to extract the conceptual nature of contextualization in mathematical problems and to analyze problems according to its conceptual framework based on the perspective of RME (Realistic Mathematical Education) which emphasizes mathematising through realistic context in mathematics textbooks of the 4th grade in Korean textbooks and the U. S. materials. "Contextualization" was analyzed by three elements such as everydayness, variety, and mathematical immanence. As results, Korean textbook showed much less in the amount of contextual problems and also represented lower contextualization in contextual problems than that of American textbooks.

• School Mathematics
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• v.16 no.1
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• pp.83-110
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• 2014

This study analyzed the mathematics textbooks of middle grades in the first Korean curriculum, based on the modern trends of mathematics education curriculum, comparing with present Korean curriculum's other textbooks and the American textbook, MiC. The mathematics textbooks in the first Korean curriculum are based on various situations in our real life and introduce mathematical concepts throughout a set of mathematics problems. The textbooks present mathematical concepts with connected knowledge and include mathematical activities which make students use mathematical table, graph and formula at the same time. And students are actively required to discuss together during the mathematics problem solving process. As the results of this modern review on Korean 1st curriculum and middle grades mathematics textbooks, it would provide preliminary data and meaningful implications for the next curriculum and concomitant instructional materials.

• Advances in Computational Design
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• v.5 no.2
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• pp.127-146
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• 2020

Building Information Modeling (BIM) is increasingly used throughout the facility's life cycle for various applications, such as design, construction, facility management, and maintenance. For existing buildings, the geometry of as-built BIM is often constructed using dense, three dimensional (3D) point clouds data obtained with laser scanners. Traditionally, as-built BIM systems do not contain the material and textural information of the buildings' elements. This paper presents a semi-automatic method for generation of material and texture rich as-built BIM. The method captures and integrates material and textural information of building elements into as-built BIM using thermal infrared sensing (TIS). The proposed method uses TIS to capture thermal images of the interior walls of an existing building. These images are then processed to extract the interior walls using a segmentation algorithm. The digital numbers in the resulted images are then transformed into radiance values that represent the emitted thermal infrared radiation. Machine learning techniques are then applied to build a correlation between the radiance values and the material type in each image. The radiance values were used to extract textural information from the images. The extracted textural and material information are then robustly integrated into the as-built BIM providing the data needed for the assessment of building conditions in general including energy efficiency, among others.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.3 no.1
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• pp.71-79
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• 1999

We consider multi-step quasi-Newton methods for unconstrained optimization. These methods were introduced by Ford and Moghrabi [1, 2], who showed how interpolating curves could be used to derive a generalization of the Secant Equation (the relation normally employed in the construction of quasi-Newton methods). One of the most successful of these multi-step methods makes use of the current approximation to the Hessian to determine the parameterization of the interpolating curve in the variable-space and, hence, the generalized updating formula. In this paper, we investigate new parameterization techniques to the approximate Hessian, in an attempt to determine a better Hessian approximation at each iteration and, thus, improve the numerical performance of such algorithms.

• Communications of Mathematical Education
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• v.25 no.1
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• pp.119-145
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• 2011

We study on the Connected Mathematics Project(CMP), one of the American mathematics education reform projects which have been promoted since the 1990s, so that we can provide some suggestions for the recent research of developing the 2009 Korean Mathematics Curriculum. In this paper, we examine the background of the CMP, the controversies over the textbooks [CMP1 textbooks] developed by CMP[CMP1] implemented from 1991 till 1996, and the curriculum of the CMP[CMP2] revised from CMP1 and carried from 2000 till 2006. Through the literature study, we can see that the CMP2 curriculum has reflected some of those controversies of the CMP1 textbooks by introducing procedures for students' acquiring basic skills, reducing the number of lessons and the contents supposed to be learned in each lesson, putting more stress on algebra and adding data analysis contents more.