• The Korean Publising Journal, Monthly
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• s.363
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• pp.27-28
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• 2006

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.4
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• pp.643-662
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• 2017

The first appearance of the equations in elementary school mathematics is in the expression of the equal sign in the addition sentences without its definition. Most elementary school students have operational understanding of the equal sign in equations. Moreover, students' opportunities to have a clear concept of the properties of operations are limited because they are used implicitly in the textbooks. Based on this fact, it has been argued that it is necessary to introduce the properties of operations explicitly in terms of specific numbers and to deal with various types of equations for understanding a relational meaning of the equal sign. In this study, we use equations to represent the implicit properties of operations and the relational meaning of the equal sign in elementary school mathematics with respect to students' level of understanding. In addition, we give some explicit examples which show how to apply them to make efficient computations.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.4
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• pp.583-599
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• 2016

In this paper, aspects of equalities with monomial left-hand side presented in Korean elementary school mathematics textbooks are analyzed focusing on the component of expressions. According to this analysis, the textbooks deal with equalities with monomial left-hand side as though the students already know them, rather than to introduce and deal with them systematically. In this paper, the following four suggestions based on this analysis are proposed as conclusions. First, A-type equalities (with one kinds of calculation symbols and two or more numbers, variables, denominative numbers in the right-hans side) and B-type equalities (with two or more kinds of calculation symbols and two or more numbers, variables, denominative numbers in the right-hans side) may need to be introduced by the explicit description. Second, it is necessary to establish clearly the order of dealing with numeric expressions, expressions with ${\Box}$(blank) expression, expressions with words, expressions with ${\Box}$(variable), expressions with variables. Third, it needs to be noted that equalities with monomial left-hand side cab be used with a variety of meanings. Fourth, it is necessary to widen the range of the number constituting equalities with monomial left-hand side to the natural number 0 and as well as fractions, decimals.

• Education of Primary School Mathematics
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• v.25 no.4
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• pp.459-475
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• 2022

The equal sign and equivalence are the most basic and core concepts in elementary mathematics, but there has been lack of research on how to teach these concepts with textbooks. Given this, this study analyzed elementary mathematics textbooks in terms of three instructional elements (i.e., emphasizing the meaning of the equal sign as a relational symbol, dealing with an equation as an object for reasoning, and using an equation with a missing value). In particular, this study analyzed 10 different mathematics textbook series that are newly used in 2022 and examined the overall trends and characteristics for teaching the equal sign and equivalence. The results of this study showed that the activities emphasizing the meaning of the equal sign as a relational symbol were most noticeable but the activities dealing with an equation as an object for reasoning or using an equation with a missing value were relatively rare. Based on the results of the analysis, this study provides textbook writers with implications on what to further consider in covering the equal sign and equivalence.

• Journal of Elementary Mathematics Education in Korea
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• v.17 no.2
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• pp.207-223
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• 2013

Teachers unfold a series of timeless mathematical symbols such as 5+2=7 in time by verbalizing the symbols in classrooms. A number sentence 5+2=7 is read in Korean as '5 더하기 2는(five plus two) 7과(seven) 같다(equals). Unlike in English, 5+2 and 7 are read first before the equal sign in Korean. This sequence of reading in Korean conflicts with the conventional linguistic sequence of writing from left to right. Ways of resolving the discrepancy between reading and writing sequences can make a difference students' understanding of the equal sign. Students would be in danger of perceiving the equal sign as an operational symbol, if a teacher resolves the discrepancy by subordinating reading sequence to linguistic convention of writing. This way of resolving results in the undesired phenomenon of changing the reading expressions in Korean elementary math textbook which represent relational notion of the equal sign into other reading expressions that represent operational notion of it. For understanding of relational notion of the equal sign, the discrepancy should be resolved by changing writing sequence in accordance with reading sequence. In addition, teaching of verbalizing the equal sign should be integrated with teaching of verbalizing inequality signs.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.129-147
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• 2002

This paper presents a variational equality formulation by Providing new dynamic route choice condition for a link-based dynamic traffic assignment model. The concepts of used paths, used links, used departure times are employed to derive a new link-based dynamic route choice condition. The route choice condition is formulated as a time-dependent variational equality problem and necessity and sufficiency conditions are provided to prove equivalence of the variational equality model. A solution algorithm is proposed based on physical network approach and diagonalization technique. An asymmetric network computational study shows that ideal dynamic-user optimal route condition is satisfied when the length of each time interval is shortened. The I-394 corridor study shows that more than 93% of computational speed improved compared to conventional variational inequality approach, and furthermore as the larger network size, the more computational performance can be expected. This paper concludes that the variational equality could be a promising approach for real-time application of a dynamic traffic assignment model based on fast computational performance.

• Education of Primary School Mathematics
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• v.27 no.1
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• pp.39-55
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• 2024

Recently, the 2022 revised mathematics curriculum has established achievement standards for equal sign and equality, and efforts have been made to examine teaching methods and student understanding of relational understanding of equal sign. In this context, this study conducted a lesson that emphasized relational understanding in an introduction to equal sign, and compared and analyzed the understanding of equal sign between the experimental group, which participated in the lesson emphasizing relational understanding and the control group, which participated in the standard lesson. For this purpose, two classes of students participated in this study, and the results were analyzed by administering pre- and post-tests on the understanding of equal sign. The results showed that students in the experimental group had significantly higher average scores than students in the control group in all areas of equation-structure, equal sign-definition, and equation-solving. In addition, when comparing the means of students by item, we found that there was a significant difference between the means of the control group and the experimental group in the items dealing with equal sign in the structure of 'a=b' and 'a+b=c+d', and that most of the students in the experimental group correctly answered 'sameness' as the meaning of equal sign, but there were still many responses that interpreted the equal sign as 'answer'. Based on these results, we discussed the implications for instruction that emphasizes relational understanding in equal sign introduction lessons.

• Journal of the Korean School Mathematics Society
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• v.19 no.3
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• pp.291-308
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• 2016

In this paper, we did a study on the definition and properties of binomial coefficients which can be seen with the topic for the enrichment of mathematically gifted students. Using this result, studied the problem of how to solve equations containing the binomial coefficients by using the mathematical induction, binomial theorem, the definition of the combination, and road network model situations. And such contents can be adequately dealt with the subject of mathematics enrichment gifted and talented Education because mathematically gifted students may well be the subject of inquiry. In addition, it can be used to study the subject to experience a deep sense of mathematics. As this research, it will be introduced as an example to guide students.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.6
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• pp.700-705
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• 2012

This paper addresses an intelligent digital redesign (IDR) technique for observer-based output-feedback control systems, in order to efficiently convert a pre-designed Takagi-Sugeno fuzzy model-based analog controller into a sampled-data one in the sense of state matching. A delta operator is used to get an asymptotic relation between the analog and the sampled-data control systems. The IDR problem is viewed as a minimization problem of the norm distances between linear operator to be matched. The condition is represented as linear matrix inequalities, and the separation principle on the IDR is shown.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.51-62
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• 2012

According to the Lighthill and Whitham's shock wave model, a shock wave exists even in a homogeneous speed condition. They referred this wave as unobservable- analogous to a radio wave that cannot be seen. Recent research has attempted to identify how such a counterintuitive conclusion results from the Lighthill and Whitham's shock wave model, and derive a new asymptotical shock wave model. The asymptotical model showed that the shock wave in a homogenous speed traffic stream is identical to the ambient vehicle speed. Thus, no radio wave-like shock wave exists. However, performance tests of the asymptotical model using numerical values have not yet been performed. We investigated the new asymptotical model by examining the implications of the new model, and tested it using numerical values based on a test scenario. Our investigation showed that the only difference between both models is in the third term of the equations, and that this difference has a crucial role in the model output. Incorporation of model parameter${\alpha}$ is another distinctive feature of the asymptotical model. This parameter makes the asymptotical model more flexible. In addition, due to various choices of ${\alpha}$ values, model calibration to accommodate various traffic flow situations is achievable. In Lighthill and Whitham's model, this is not possible. Our numerical test results showed that the new model yields significantly different outputs: the predicted shock wave speeds of the asymptotical model tend to lean toward the downstream direction in most cases compared to the shock wave speeds of Lighthill and Whitham's model for the same test environment. Statistical tests of significance also indicate that the outputs of the new model are significantly different than the corresponding outputs of Lighthill and Whitham's model.