• Journal of The Korean Association For Science Education
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• v.7 no.2
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• pp.89-95
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• 1987

Historically, one of the most famous and endless controversies in science and science education is on the origin of life. Since 1859, when the 1st edition of 'On The Origin Of Species' written by Charles Darwin had been published in London. evolutionism had the support of the public and scholars Creationists. however, argue recently that the scientific creationism is supported by the vast geological, biological, palaeontological biochemical and even astronomical evidences. Strong arguments of creationists stirred up the sharpening critiques of evolutionists. In this paper. the author summarizes three recent evolutionary critiques on creationism and refutes them from creationist view. After examing the critiques. we find that they are not based on the decisive evolutionary evidences but considerable conjectures And we show that the majority of critiques stem from the lack of communication in the academic communities.

• Honam Mathematical Journal
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• v.27 no.3
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• pp.399-404
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• 2005

Let M be a finite commutative nilpotent algebra over a perfect field k of prime characteristic p and let $M^p$ be the sub-algebra of M generated by $x^p$, $x{\in}M$. Eggert[3] conjectures that $dim_kM{\geq}pdim_kM^p$. In this paper, we show that the conjecture holds for $M=R^+/I$, where $R=k[X_1,\;X_2,\;{\cdots},\;X_t]$ is a polynomial ring with indeterminates $X_1,\;X_2,\;{\cdots},\;X_t$ over k and $R^+$ is the maximal ideal of R generated by $X_1,\;X_2,{\cdots},\;X_t$ and I is a monomial ideal of R containing $X_1^{n_1+1},\;X_2^{n_2+1},\;{\cdots},\;X_t^{n_t+1}$ ($n_i{\geq}0$ for all i).

• Bulletin of the Korean Mathematical Society
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• v.60 no.4
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• pp.915-931
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• 2023

Let F_n be the Farey sequence of order n. For S ⊆ F_n, let 𝓠(S) be the set of rational numbers x/y with x, y ∈ S, x ≤ y and y ≠ 0. Recently, Wang found all subsets S of F_n with |S| = n + 1 for which 𝓠(S) ⊆ F_n. Motivated by this work, we try to determine the structure of S ⊆ F_n such that |S| = n and 𝓠(S) ⊆ F_n. In this paper, we determine all sets S ⊆ F_n satisfying these conditions for n ∈ {p, 2p}, where p is prime.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.542-547
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• 2001

A non-intrusive Planar Laser-Induced Fluorescence(PLIF) technique was applied to study the turbulent mixing process in a Rushton turbine reactor. Instantaneous and ensemble averaged concentration fields are obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by a thin Nd:Yag laser sheet illuminating the whole center plane of the stirred tank. The gray level images captured by a 14-bit cooled CCD camera can be transformed to the local concentration values using a calibration matrix. The dye injection point was selected at the tank wall with three quarter height (3/4H) from the tank bottom to observe the mixing characteristics in upper bulk flow region. There exist distinct two time scales: the rapid decay of mean concentration in each region after the dye infusion reflects the large scale mixing while the followed slow decay reveals the small scale mixing. The temporal change of concentration probability functions conjectures the two sequential processes in the batch type mixing. An inactive column of water existed above the impeller disk, in which the fluid rotates with the shaft but is isolated from the mean bulk flow.

• The Mathematical Education
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• v.45 no.4 s.115
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• pp.481-491
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• 2006

Diffy is a simple mathematical puzzle that provides elementary-school students with subtraction practice. The idea appears to have originated in the late nineteenth century with E. Ducci of Itali. Thirty years ago Professor J. Copley of the University of Houston introduced the diffy game to teachers in elementary schools and it widely spreaded out. During the diffy activity we naturally guess many interesting conjectures. First, does diffy always end? Second, does the head of diffy always exist? Third, for an arbitrary given natural number n, is there any possible method to find the diffy with the given length n? In this study I give the necessary and sufficient condition for the existence of the head of diffy. Using this condition I classify all possible heads of diffy and provide an algorithm to find the diffy with any given length n. With this algorithm I find four natural numbers with diffy length 200. To ensure my numbers are correct, I make a diffy program for Mathematica and check they are correct. I suggest the diffy game is good for enlarging the mathematical thinking to all graded students, especially gifted and talented students, It will produce rational consideration and synthetic judgement.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.8
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• pp.1145-1152
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• 2002

A non-intrusive Planar Laser-Induced Fluorescence(PLIF) technique was applied to study the turbulent mixing process in a Rushton turbine reactor. Instantaneous and ensemble averaged concentration fields was obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by a thin Nd:Yag laser sheet illuminating the whole center plane of the stirred tank. The gray level images captured by a 14-bit cooled CCD camera could be transformed to the local concentration values using a calibration matrix. The dye injection point was selected at the tank wall with three quarter. height (3/4H) from the tank bottom to observe the mixing characteristics in upper bulk flow region. There exist distinct two time scales: the rapid decay of mean concentration after the dye infusion reflects the large scale turbulent mixing while the fellowed slow decay reveals the small scale molecular mixing. The temporal change of concentration variance field conjectures the two sequential processes for the batch type mixing. An inactive column of water is existed above the impeller disk, in which the fluid rotates with the shaft but is isolated from the mean bulk flow.

• Journal of the Korean earth science society
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• v.31 no.5
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• pp.521-530
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• 2010

This study aimed to explore how to characterize the earth science inquiry in schools in terms of science teaching interaction and constructivist teaching practice. The constructivist teaching practices were analyzed with Reformed Teaching Observation Protocol (RTOP) in three aspects including (1) student oriented class implementation, (2) subject knowledge and representation, and (3) classroom communication. Fourteen earth science classes were observed and scored with RTOP. The class was evaluated to be transitional stage in terms of constructivist teaching, e.g., moving toward student-centered teaching practice. Especially, Korean teachers tend to lean their classes more on propositional knowledge than procedural knowledge. To interpret science teaching interactions, an earth science teacher with a RTOP top rank was selected. Her class was then videotaped for detailed analysis. I adopted the analytical framework of communicative approaches and discourse patterns among the five aspects of interactions presented by Mortimer and Scott (2003). It was found that this earth science teacher used more authoritative patterns than the dialogic. In addition, she used IRE discourse pattern more frequently. Interestingly, teachers interacted with their students more frequently in the form of repeated (or IRE chain pattern), that is IRFRF (teacher initiation-student response-teacher feedback-student response-teacher feedback) in the context of dialogic communicative approaches, while simple IRE occurred in an authoritative approach. In earth science classrooms, typical interaction may well be constructed in the form of IRFRF chains to allow students free conjectures and abduction.

• Journal of Educational Research in Mathematics
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• v.20 no.1
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• pp.57-71
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• 2010

Similarity between concept and concept, principle and principle, theory and theory is known as a strong motivation to mathematical knowledge construction. Metaphor and analogy are reasoning skills based on similarity. These two reasoning skills have been introduced as useful not only for mathematicians but also for students to make meaningful conjectures, by which mathematical knowledge is constructed. However, there has been lack of researches connecting the two reasoning skills. In particular, no research focused on the interplay between the two in didactic transposition. This study investigated the process of knowledge construction by metaphor and analogy and their roles in didactic transposition. In conclusion, three kinds of models using metaphor and analogy in didactic transposition were elaborated.

• Journal of The Korean Association For Science Education
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• v.13 no.2
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• pp.152-162
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• 1993

The high school students' problem solving patterns and their features in scientific inquiry, especially on controlling variables and stating hypothesis have been investigated. The 8 problems on controlling variables and stating hypothesis were selected out of the scientific inquiry area in the experimental tryout of Aptitude Assessment for College Education, and had been used to find the patterns and their features. The results of findings are as follows: There were seven patterns in the process of solving problems. Five of seven patterns were found in right answers and four patterns in wrong answers. Two patterns were found in both right and wrong answers. Some students could solve the problems even though they did not understand the elements of the scientific inquiry, controlling variables and stating hypothesis. The false application of physics concepts, misunderstanding about the elements of the scientific inquiry and using unrelated experience and conjectures were the features of students' wrong answers. On the other hand, the right application of physics concepts, understanding and applying the elements right, infering answers from the tables and figures on statements of suggested problems were the features of right answers. The further studies on this kind may helpful to find the higher mental abilities related to scientific inquiry and to develop tools for testing students' scientific inquiry thinking skills.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.11 s.254
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• pp.1051-1056
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• 2006

The mean and RMS velocity field of the respiratory gas flow in the human airway was studied experimentally by particle image velocimetry (PIV). Some researchers investigated the airflow for the mouth breathing case both experimentally and numerically. But it is very rare to investigate the airflow of nose breathing in a whole airway due to its geometric complexity. We established the procedure to create a transparent rectangular box containing a model of the human airway for PIV measurement by combination of the RP and the curing of clear silicone. We extend this to make a whole airway including nasal cavities, larynx, trachea, and 2 generations of bronchi. The CBC algorithm with window offset (64 $\times$ 64 to 32 $\times$ 32) is used for vector searching in PIV analysis. The phase averaged mean and RMS velocity distributions in Sagittal and coronal planes are obtained for 7 phases in a respiratory period. Some physiologic conjectures are obtained. The main stream went through the backside of larynx and trachea in inspiration and the frontal side in expiration. There exist vortical motions in inspiration, but no prominent one in expiration.