• Journal of Fisheries and Marine Sciences Education
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• v.26 no.4
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• pp.902-914
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• 2014

The purpose of this study is to provide useful information by analysis on mathematic classes for improve interactions between teacher and student using the Flanders Category System. For this, mathematic classes were observed by videotapes and recorded, 10 recorded videotapes were selected for analysis the property of linguistic interaction. The collected videotapes and records materials were transcribed by Advanced Flanders(AF) analysis program version 3.54. The detail investigated topics for studying are as follows. 1) What is the property of the Flanders 10 code analysis results? 2) What is the property of main and subsidiary linguistic flow of interaction? 3) What is the property of the Flanders index analysis results? The results of this study are as follow: 1) In Flanders 10 code analysis results, teacher's non-directive speaking is 12.76%, teacher's Indicative speaking is 50.28%, student's reactive speaking is 4.07%, student's voluntary speaking is 9.66%. 2) Among the 10 classes, 5 classes' main flow is 'ask convergent question ${\rightarrow}$ student's reactive speaking ${\rightarrow}$ lecture ${\rightarrow}$ ask convergent question', 2 classes' main flow is 'lecture ${\rightarrow}$ ask convergent question ${\rightarrow}$ student's reactive speaking ${\rightarrow}$ lecture', 3 classes' main and subsidiary flow is 'lecture ${\rightarrow}$ ask convergent question ${\rightarrow}$ lecture ${\rightarrow}$ work'. 3) In indices results, revised I/d ratio, student's speaking ratio, student question, wide answer ratio are higher than analysis standard and indirect ratio, teacher's question ratio are lower than analysis standard.

• Environmental Engineering Research
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• v.25 no.4
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• pp.529-535
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• 2020

The present study investigated the photodegradation of synthetic organic dye; violet-3B, without and with the addition of C-N-codoped TiO₂ catalyst using a visible halogen-lamp as a light source. The catalyst was synthesized by using a peroxo sol-gel method with free-organic solvent. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of violet-3B were examined. The efficiency of the photodegradation process for violet-3B dye was higher at neutral to less acidic pH. The kinetics reaction rate of photodegradation of violet-3B dye with the addition of C-N-codoped TiO₂ followed pseudo-first order kinetics represented by the Langmuir-Hinshelwood model, and increasing the initial concentration of dyes decreased rate constants of photodegradation. Photodegradation of 5 mg L^-1 violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO₂ catalyst, and approximately 44% TOC was removed as a result of the mineralization.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.23-30
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• 2021

In this paper, we established the generalized thermoelasticity phenomenon in an isotropic elastic medium considering the electromagnetic field, rotation and two-temperature. Three theories of generalized thermoelasticity have been applied: Lord-Shulman (one relaxation time), Green-Lindsay (two relaxation times), as well as the coupled theory. We discussed some particular cases in the context of the wave propagation phenomenon in thermoelasticity. From solving the fundamental equations, we arrived that there are three waves: P-, T- and SV-waves that we calculated their velocities. The boundary conditions for mechanical stress and Maxwell's stress and thermal insulated or isothermal have been applied to determine the amplitudes ratios (reflection coefficients) for P-, T - and SV waves. Some utilitarian aspects are obtained from the reflection coefficients, presented graphically, and the new conclusions have been presented. Comparisons are made for the results predicted by different theories (CT, LS, GL) in the absence and presence of the electro-magnetic field, rotation, as well as two-temperature on the reflection of generalized thermoelastic waves. The results obtained concluded that the external parameters as the angle of incidence, electromagnetic field, rotation as well as the theories parameters have strong effect on the phenomenon.

• Communications of the Korean Mathematical Society
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• v.7 no.2
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• pp.189-207
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• 1992

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2001.10a
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• pp.81-87
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• 2001

In this article, we have done some analysis about the collision-avoidance specialty of “pressing complexion” and “pressing danger”in the meet process of two boats, and offered a mathematic model of differential coefficient countermeasure decision for collision-avoidance, which adapt to the right complexion. The basal idea is, in the right condition whatever do the coming boat do, and our boat will always adept dynamic, continuous and the best countermeasure. When both the controlling capabilities of two boats have advantage and inferior position, we can working-out with the qualitative differential coefficient countermeasure.

• Journal of Educational Research in Mathematics
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• v.8 no.1
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• pp.327-350
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• 1998

The purpose of this study is to examine the applicability of educational games to open mathematic learning and consideration to the position of educational games in mathmatical education as powerful technology. For these purposes, previous literatures about games are reviewed. The concept of simulation games are defined and explore the characteristics of games includings game structure and process. And some typical educational games - Israel games, ORDA - are introduced. The main focus of the deliberation and survey of previous literatures is educational games as meaningful learning medium of mathematics and other subjuct matters. Especially educational games take a meaningful role for an implication of applicability of games especially for higher order thinking skills like problem solving, decision making, and creativity. To realize this alternative learning method of mathematics, first of all the attituce of teachers are have to change and accumulate field studies.

• Bulletin of the Korean Mathematical Society
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• v.50 no.1
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• pp.105-116
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• 2013

In this paper, we consider the positive solution to a Cauchy problem in $\mathbb{B}^N$ of the fast diffusive equation: ${\mid}x{\mid}^mu_t={div}(\mid{\nabla}u{\mid}^{p-2}{\nabla}u)+{\mid}x{\mid}^nu^q$, with nontrivial, nonnegative initial data. Here $\frac{2N+m}{N+m+1}$ < $p$ < 2, $q$ > 1 and 0 < $m{\leq}n$ < $qm+N(q-1)$. We prove that $q_c=p-1{\frac{p+n}{N+m}}$ is the critical Fujita exponent. That is, if 1 < $q{\leq}q_c$, then every positive solution blows up in finite time, but for $q$ > $q_c$, there exist both global and non-global solutions to the problem.

• Research in Mathematical Education
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• v.19 no.4
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• pp.247-265
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• 2015

Mathematics textbook plays a significant role in shaping students' learning of mathematics. Logic, rigor and abstraction as typical features of the formalization of mathematics, dominate mathematics textbooks around the world, which is regarded as one of the important origins of students' learning difficulties in mathematics. An innovative series of Chinese mathematic textbooks is presented in this paper. Supported by the supplementary materials excerpts from the textbooks, it gives a comprehensive theoretical analysis of the principles of design and implementation of this series of mathematics textbooks. The effectiveness of this series of textbooks is demonstrated by student achievement and secondary research data. It shows that series of Chinese mathematic textbooks has largely decreased students' learning difficulties in mathematics and enhance classroom teaching efficiency. It suggests that prioritizing the essence of mathematics and reducing abstraction is an important notion for mathematics textbook design and implementation.

• Communications of the Korean Mathematical Society
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• v.13 no.1
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• pp.77-84
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• 1998

In this note we show that if $T_{\varphi}$ is a Toeplitz operator with quasicontinuous symbol $\varphi$, if $\omega$ is an open set containing the spectrum $\sigma(T_\varphi)$, and if $H(\omega)$ denotes the set of analytic fuctions defined on $\omege$, then the following statements are equivalent: (a) $T_\varphi$ is semi-quasitriangular. (b) Browder's theorem holds for $f(T_\varphi)$ for every $f \in H(\omega)$. (c) Weyl's theorem holds for $f(T_\varphi)$ for every $f \in H(\omega)$. (d) $\sigma(T_{f \circ \varphi}) = f(\sigma(T_varphi))$ for every $f \in H(\omega)$.

• The Mathematical Education
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• v.53 no.4
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• pp.525-539
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• 2014

In this study, we suggest implications for teaching mathematical justification with analysis of 6th grade students' awareness of why they needed mathematical justification and their levels of mathematics justification in Algebra and Geometry. Also how their levels of mathematical justification were related to mathematic achievement. 96% of students thought mathematical justification was needed, the reasons were limited for checking their solutions and answers. The level of mathematical justification in Algebra was higher than in Geometry. Students who had higher mathematic achievement had higher levels of mathematical justification. In conclusion, we searched the possibility of teaching mathematical justification to students, and we found some practical methods for teaching.