• Journal of Educational Research in Mathematics
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• v.23 no.2
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• pp.285-295
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• 2013

In this study I examine the definitions of terms related to ratio and rate from 5, 6, 7th revised elementary school math textbooks to discuss the improvements and the remained problems in 2007 curriculum textbook. Next, I make the alternative definitions of the terms, 'biyoul', the value of 'bi', and 'baekboonyul' by re-establishing the relations between them. Finally, I point out that those problems are intrinsic to the attempt of the textbook to introduce the terms related to ratio with little consideration for the mathematical meaning of ratio as a equivalence class.

• BMB Reports
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• v.37 no.1
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• pp.83-92
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• 2004

As a result of the enormous amount of information that has been collected with E. coli over the past half century (e.g. genome sequence, mutant phenotypes, metabolic and regulatory networks, etc.), we now have detailed knowledge about gene regulation, protein activity, several hundred enzyme reactions, metabolic pathways, macromolecular machines, and regulatory interactions for this model organism. However, understanding how all these processes interact to form a living cell will require further characterization, quantification, data integration, and mathematical modeling, systems biology. No organism can rival E. coli with respect to the amount of available basic information and experimental tractability for the technologies needed for this undertaking. A focused, systematic effort to understand the E. coli cell will accelerate the development of new post-genomic technologies, including both experimental and computational tools. It will also lead to new technologies that will be applicable to other organisms, from microbes to plants, animals, and humans. E. coli is not only the best studied free-living model organism, but is also an extensively used microbe for industrial applications, especially for the production of small molecules of interest. It is an excellent representative of Gram-negative commensal bacteria. E. coli may represent a perfect model organism for systems biology that is aimed at elucidating both its free-living and commensal life-styles, which should open the door to whole-cell modeling and simulation.

• Journal of Educational Research in Mathematics
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• v.25 no.3
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• pp.449-460
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• 2015

As a main body of a curriculum, a set of sentences stating mathematical contents plays an important role in teaching and learning mathematics. The contents sentences in the $7^{th}$ version, the 2007 version, and the 2009 version of elementary mathematics curricula were analysed. The elementary mathematics curriculum consists of about 200 contents sentences. The final endings of those sentences are the type of ability such as "to be able to ~". The elementary mathematics curriculum would be managed systematically by disassembling and restructuring those contents sentences. We should state students' activities more concretely by varying the final endings in the curriculum.

• School Mathematics
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• v.15 no.2
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• pp.369-387
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• 2013

This research intends to give a practice of mathematics lesson-critique and some perspectives on a mathematics lesson in the elementary school level. We carried out a mathematics lesson-critique on a lesson chosen as a good lesson by a local educational district in Korea. The main themes of mathematics lesson-critique were the reconstruction of lesson models, the pursuit of relational understanding, the activation of mathematical communication, and the didactical transformation by a in-service teacher. Meanwhile we confirmed that we need to discuss the properness and adequateness of contents about division of natural numbers given in the elementary mathematics textbook and teachers' guide according to the revised 2007 mathematics curriculum.

• School Mathematics
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• v.4 no.1
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• pp.15-27
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• 2002

The purpose of this thesis is, through analysing the characteristics of the definitions in Korean school mathematics textbooks, to explore the levels of them. Definitions use din academic mathematics are rigorous. But they should be transformed into various types, which are presented in school mathematics textbooks, with didactical purposes. In this thesis we investigated such types of transformation. With the result of this investigation we tried to identify the levels of the definitions in school mathematics textbooks. We tried to construct, with consideration about methods of definition, frame for analysing the types of the definitions in school mathematics. Methods of definition are classified as connotative method, denotative method, and synonymous method. Especially we identified that connotative method contains logical definition, genetic definition, relational definition, operational definition, and axiomatic definition. With these analyses we made a frame for investigating the characteristics of the definitions in school mathematics textbooks. With this frame we identified concrete types of transformations of methods of definition. We tried to analyse this result with van Hieles' theory about let·els of geometry learning and the mathematical language levels described by Freudenthal, and identify the levels of definitions in school mathematics. We showed the levels of definitions in the geometry area of the Korean school mathematics.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.245-261
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• 1999

Proof is an essential characteristic of mathematics and as such should be a key component in mathematics education. But, teaching proof in school mathematics have been unsuccessful for many students. The traditional approach to proofs stresses formal logic and rigorous proof. Thus, most students have difficulties of the concept of proof and students' experiences with proof do not seem meaningful to them. However, different views of proof were asserted in the reassessment of the foundations of mathematics and the nature of mathematical truth. These different views of justification need to be reflected in demonstrative geometry classes. The purpose of this study is to characterize the types of students' justification in demonstrative geometry classes taught using dynamic software. The types of justification can be organized into three categories : empirical justification, deductive justification, and authoritarian justification. Empirical justification are based on evidence from examples, whereas deductive justification are based logical reasoning. If we assume that a strong understanding of demonstrative geometry is shown when empirical justification and deductive justification coexist and benefit from each other, then students' justification should not only some empirical basis but also use chains of deductive reasoning. Thus, interaction between empirical and deductive justification is important. Dynamic geometry software can be used to design the approach to justification that can be successful in moving students toward meaningful justification of ideas. Interactive geometry software can connect visual and empirical justification to higher levels of geometric justification with logical arguments in formal proof.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.89-99
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• 2011

Digital edutainment games and educational content to the concept of combining learning and to draw conclusions that can be varied and fun learning program. Yet effective design. There's a lot of discussion about the systematic and scientific research, explore the difficult, but so is the growing field of endless possibility. Merely a linguistic capabilities of human intelligence and mathematical ability were measured primarily on issues raised in the traditional intelligence tests, and emerged a variety of multiple intelligences theory of human intelligence classified into 8 types and characteristics of each intelligence activities and guidelines for faculty are presented. These lessons are based on multiple intelligences theory professor activities through the design study for students to form learning activities to meet effectively and systematically conducted classes, and student-specific classes can be designed. In this study, multiple intelligences theory, based on children's edutainment content by linguistic intelligence, and intrapersonal intelligence body-kinestic intelligent and can learn by linking to content that was designed. Children interested in animation and gaming content through the feeling that you can become stiff in Korean alphabet education to solve the quests were designed to be a natural puleonagal.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.2
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• pp.119-127
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• 2014

An epoxy coating applied to the concrete surface of a containment building deteriorates in hazardous environments such as those containing radiation, heat, and moisture. Unlike metals, the epoxy coating on a concrete liner absorbs and discharges moisture during the degradations process, so it has a different density and volume during service. In this study, acoustic impedance was adopted for characterizing the degradation of a glass-reinforced epoxy coating using the acoustic reflection coefficient (reflectance) on a rough epoxy coating. For estimating the acoustic reflectance on a wavy epoxy coating surface, a probabilistic model was developed to represent the multiple irregular reflections of the acoustic wave from the wavy surface on the basis of the simulated annealing technique. A number of epoxy-coated concrete specimens were prepared and exposed to accelerated aging conditions to induce an artificial aging degradation in them. The acoustic impedance of the degraded epoxy coating was estimated successfully by minimizing the error between a waveform calculated from the mathematical model and a waveform measured from the surface of the rough coating.

• ETRI Journal
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• v.44 no.4
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• pp.641-653
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• 2022

In the process of autonomous vehicle motion planning and to create comfort for vehicle occupants, factors that must be considered are the vehicle's safety features and the road's slipperiness and smoothness. In this paper, we build a mathematical model based on the combination of a genetic algorithm and a neural network to offer lane-change solutions of autonomous vehicles, focusing on human vehicle control skills. Traditional moving planning methods often use vehicle kinematic and dynamic constraints when creating lane-change trajectories for autonomous vehicles. When comparing this generated trajectory with a man-generated moving trajectory, however, there is in fact a significant difference. Therefore, to draw the optimal factors from the actual driver's lane-change operations, the solution in this paper builds the training data set for the moving planning process with lane change operation by humans with optimal elements. The simulation results are performed in a MATLAB simulation environment to demonstrate that the proposed solution operates effectively with optimal points such as operator maneuvers and improved comfort for passengers as well as creating a smooth and slippery lane-change trajectory.

• Steel and Composite Structures
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• v.50 no.4
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• pp.403-418
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• 2024

In this paper, vibration and energy absorption characteristics of a nanostructure which is composed of two embedded porous annular/circular nanoplates coupled by a viscoelastic substrate are investigated. The modified couple stress theory (MCST) and the Gurtin-Murdoch theory are applied to take into account the size and the surface effects, respectively. Furthermore, the structural damping effect is probed by the Kelvin-Voigt model and the mathematical model of the problem is developed by a new hyperbolic higher order shear deformation theory. The differential quadrature method (DQM) is employed to obtain the out-of-phase and in-phase frequencies of the structure in order to predict the dynamic response of it. The acquired results reveal that the vibration and energy absorption of the system depends on some factors such as porosity, surface stress effects, material length scale parameter, damping and spring constants of the viscoelastic foundation as well as geometrical parameters of annular/circular nanoplates. A bird's-eye view of the findings in the research paper offers a comprehensive understanding of the vibrational behavior and energy absorption capabilities of annular/circular porous nanoplates. The multidisciplinary approach and the inclusion of porosity make this study valuable for the development of innovative materials and applications in the field of nanoscience and engineering.