• Journal of Science Education
• /
• v.47 no.3
• /
• pp.263-272
• /
• 2023

We consider how a pre-service teacher can understand and utilize various concepts of Euclidean geometry by learning conic sections using mathematical definitions in non-Euclidean geometry. In a third-grade class of D University, we used mathematical definitions to demonstrate that learning conic sections in non-Euclidean space, such as taxicab geometry and Minkowski distance space, can aid pre-service teachers by enhancing their ability to acquire and accept new geometric concepts. As a result, learning conic sections using mathematical definitions in taxicab geometry and Minkowski distance space is expected to contribute to enhancing the education of pre-service teachers for Euclidean geometry expertise by fostering creative and flexible thinking.

• Honam Mathematical Journal
• /
• v.34 no.1
• /
• pp.103-111
• /
• 2012

Wetzel[5] proved if ${\Gamma}$ is a closed curve of length L in $E^n$, then ${\Gamma}$ lies in some ball of radius [L/4]. In this paper, we generalize Wetzel's result to the non-Euclidean plane with much stronger version. That is to develop a lower bound of length of a triangle inscribed in a circle in non-Euclidean plane in terms of a chord of the circle.

• Korean Journal of Mathematics
• /
• v.25 no.4
• /
• pp.537-554
• /
• 2017

In this paper, we study the surfaces foliated by ellipses in three dimensional Euclidean space ${\mathbf{E}}^3$. We prove the following results: (1) The surface foliated by an ellipse have constant Gaussian curvature K if and only if the surface is flat, i.e. K = 0. (2) The surface foliated by an ellipse is a flat if and only if it is a part of generalized cylinder or part of generalized cone.

• Journal of applied mathematics & informatics
• /
• v.34 no.3_4
• /
• pp.309-317
• /
• 2016

Let V be a Euclidean Jordan algebra with a symmetric cone K. We show that for a Z-transformation L with the additional property L(K) ⊆ K (which we will call ’cone-preserving’), GUS ⇔ strictly copositive on K ⇔ monotone + P. Specializing the result to the Stein transformation S_A(X) := X - AXA^T on the space of real symmetric matrices with the property $S_A(S^n_+){\subseteq}S^n_+$, we deduce that S_A GUS ⇔ I ± A positive definite.

• Journal for History of Mathematics
• /
• v.24 no.4
• /
• pp.21-31
• /
• 2011

In this paper I claim that Lobachevsky's philosophy of mathematics is a kind of reservoir of contemporary philosophy of mathematics. I discuss how his philosophy contributed to the rise of non-Euclidean geometry.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.5C
• /
• pp.611-617
• /
• 2004

The optimum convolutional error correction codes for recently standardized Feher-patented quadrature phase-shift keying (FQPSK-B) modulation are proposed. We utilize the continuous phase modulation characteristics of FQPSK-B signals for calculating the minimum Euclidean distance of convolutional coded FQPSK-B signal. It is shown that the Euclidean distance between two FQPSK-B signals is proportional to the Hamming distance between two binary data sequence. Utilizing this characteristic, we show that the convolutional codes with optimum free Hamming distance is the optimum convolutional codes for FQPSK-B signals.

• Honam Mathematical Journal
• /
• v.30 no.4
• /
• pp.637-644
• /
• 2008

In this paper, we study some properties about the parallel surfaces of ruled surfaces in a Euclidean 3-space. Furthermore, we classify the parallel surfaces of ruled surfaces in a Euclidean 3-space satisfying a linear type and a quadric type with respect to the Gaussian curvature and the mean curvature.

• East Asian mathematical journal
• /
• v.31 no.5
• /
• pp.677-684
• /
• 2015

In [7], it was shown that Euclidean rings R of imaginary quadratic integers admit unitary number systems. In this paper, as an application of the result, we obtain all self similar tiles arising from the unitary number systems of R.

• Journal for History of Mathematics
• /
• v.16 no.2
• /
• pp.23-34
• /
• 2003

In this paper, we consider relationship between the mathematics and the fine arts. The former is one of the advanced sciences, the latter is one of the arts. But there is correlation between the mathematics and the arts. Here, we concern with the ancient greek mathematics, Euclidean geometry and the ancient greek arts. The ancient greek arts is classified with Geometric Style, Archaic Style, Classical Style and Hellenistic Style. The Geometric Style, Classical Style and Hellenistic Style are very effected by Euclidean geometry. Because the greek artists as keep the geometric proportion as the Euclidean's 5th postulates. The artist's cannon in just golden ratio 1:(1＋$\sqrt{5}$)/2.

• Journal of applied mathematics & informatics
• /
• v.9 no.1
• /
• pp.441-447
• /
• 2002

We show that the conharmonical1y flat K-contact find cosymplectic manifolds are local1y Euclidean. Evidently non locally Euclidean conharmonically flat Sasakian manifold does not exist. Moreover we see that conharmonically flat Kenmotsu manifold does not exist and conharmonically flat fibred quasi quasi Sasakian space is locally Euclidean if and only if the scalar curvature of each fibre vanishes identically.