• East Asian mathematical journal
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• v.31 no.1
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• pp.33-40
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• 2015

We study the geometry of r-lightlike submanifolds M of a semi-Riemannian manifold $\bar{M}$ with a semi-symmetric non-metric connection subject to the conditions; (a) the screen distribution of M is totally geodesic in M, and (b) at least one among the r-th lightlike second fundamental forms is parallel with respect to the induced connection of M. The main result is a classification theorem for irrotational r-lightlike submanifold of a semi-Riemannian manifold of index r admitting a semi-symmetric non-metric connection.

• Journal of Applied Reliability
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• v.12 no.4
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• pp.265-274
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• 2012

We in this paper discuss the strong law of large numbers for weighted sums of arrays of rowwise LNQD random variables by using a new exponential inequality of LNQD r.v.'s under suitable conditions and we obtain one of corollary.

• Journal of the Korean Mathematical Society
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• v.42 no.3
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• pp.471-484
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• 2005

We study Riemannian or pseudo-Riemannian manifolds which carry the space of closed conformal vector fields of at least 2-dimension. Subject to the condition that at each point the set of closed conformal vector fields spans a non-degenerate subspace of the tangent space at the point, we prove a global and a local classification theorems for such manifolds.

• Journal for History of Mathematics
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• v.17 no.3
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• pp.109-120
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• 2004

This study investigated three pre-service teachers' mathematical problem solving among hand-in-write-ups and final projects for each subject. All participants' activities and computer explorations were observed and video taped. If it was possible, an open-ended individual interview was performed before, during, and after each exploration. The method of data collection was observation, interviewing, field notes, students' written assignments, computer works, and audio and videotapes of pre- service teachers' mathematical problem solving activities. At the beginning of the mathematical problem solving activities, all participants did not have strong procedural and conceptual knowledge of the graph, making a model by using data, and general concept of a sine function, but they built strong procedural and conceptual knowledge and connected them appropriately through mathematical problem solving activities by using the computer technology.

• Journal for History of Mathematics
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• v.18 no.1
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• pp.11-32
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• 2005

This paper is a comprehensive study of mathematics education in the Chosun Dynasty. The basis of this work relies on actual historical records from the period. As shown in the records, mathematics education during the Chosun Dynasty remained at the level of basic arithmetics. The arithmeticians of the Chosun Dynasty did not have an understanding of more complex mathematical thought. But the simple arithmetics of the Chosun Dynasty facilitated the building up of a unique merchant 'middle class.' So this paper examines the development of mathematics in the Chosun Dynasty through middle class. Although the Chosun Dynasty arithmetics occupy a significant part of mathematics history, this paper details why their thought did not evaluate more advanced mathematical theories.

• Journal for History of Mathematics
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• v.17 no.4
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• pp.123-132
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• 2004

In this paper, we reviewed the history of mathematical problem solving since 1900 and investigated problem solving in modeling perspective which is focused on the 21th century. In modeling perspective, problem solvers solve the realistic problem which includes contextualized situations in which mathematics is useful. In this case, the problem is different from the traditional problems which are routine, close, and words problem, etc. Problem solving in modeling perspective emphasizes mathematizing. Most of all, what is important enables students to use mathematics in everyday problem solving situation.

• Journal for History of Mathematics
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• v.18 no.1
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• pp.33-48
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• 2005

The Rule of False Position is known as an arithmetical solution of algebraical equations. On the other hand, the Excess-Deficit Rule is an algorithm for calculating about excessive or deficient quantitative relations, which is found in the ancient eastern mathematical books, including the nine chapters on the mathematical arts. It is usually said that the origin of the Rule of False Position is the Excess-Deficit Rule in ancient Chinese mathematics. In relation to these facts, we pose two questions: - As many authors explain, the excess-deficit rule is a solution of simultaneous linear equations？ - Which relation is there between the two rules explicitly？ To answer these Questions, we consider the Rule of Single/Double False Position and research the Excess-Deficit Rule in some ancient mathematical books of Chosun Dynasty that was heavily affected by Chinese mathematics. And we pursue their historical traces in Egypt, Arab and Europe. As a result, we can make sure of the status of the Excess-Deficit Rule differing from the Rectangular Arrays(the solution of simultaneous linear equations) and identify the relation of the two rules: the application of the Excess-Deficit Rule including supposition in ancient Chinese mathematics corresponds to the Rule of Double False Position in western mathematics. In addition, we try to appreciate didactical value of the Rule of False Position which is apt to be considered as a historical by-product.

• Education of Primary School Mathematics
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• v.21 no.2
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• pp.193-208
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• 2018

Classification is presented in the curriculum of elementary school mathematics, science, Korean language, and integrated subjects as the major function that needs to be learned. In addition, mathematics textbooks teach the classification as a basic process for organizing and interpreting collected materials in a separate unit. So, we analyzed the curriculum documents and textbooks of mathematics, science, Korean language, and integrated subjects. And we explored how to teach the classification in the context of mathematics subject. As a result, it is necessary to find different classification criteria in conjunction with detailed observation and investigation activities, and to teach that considering the circumstances and purpose of the classification. It also provided implications on how to revive converged classes that focus on big ideas and skills, which are commonly offered by various subjects.

• Journal for History of Mathematics
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• v.17 no.4
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• pp.133-152
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• 2004

In this paper, we discuss students' conceptual development of eigen value and eigen vector in differential equation course based on reformed differential equation using the mathematical model of mass spring according to historico-generic principle. Moreover, in setting of small group interactive learning, we investigate the students' development of mathematical attitude.

• Journal for History of Mathematics
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• v.9 no.2
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• pp.1-9
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• 1996

This paper is a sequel to [26]. We investigate how the Axiom of Choice has been accepted after Zermelo introduced the Axiom in 1904. The response to the Axiom has divided into two groups of mathematicians, namely idealists and empiricists. We also investigate how the Zorn's lemma (1935) has been emerged. It was originally formulated by Hausdorff in 1909 and then by many other mathematicians independently.