• The Mathematical Education
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• v.41 no.1
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• pp.19-34
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• 2002

The 7th national mathematics curriculum lays emphasis on an interrelation of several subjects and a connection between mathematics and real life. In this reason, this study focuses on the enhancement of sound understanding nuclear energy which is one of important factor(concepts or contents) dealt with in the other subjects such as science, environment, social studies, etc.. Recently, even though it is insistent that nuclear energy be so important and request in the future society, there are still strong pro and cons regarding the use of it. In this study, teaching-and-learning materials were developed dealing with using nuclear energy, and consequently they might be used in math class for the purpose of enhancement of mathematical learning ability and of recognition on nuclear energy. In this study, Material 1 included a matter of the necessity for nuclear power plants using the ratio concept, and Material 2 did on a matter of the efficiency of nuclear energy and the unclear of nuclear power plants using ratio-graph, in the elementary and upper school mathematics. Material 3 focused on a matter of the principles of nuclear power plants using the properties of exponential law in high school mathematics. Ultimately, it is hoped in the study that more diverse instructional materials dealing with diverse situations inside and outside mathematics would be developed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.162-163
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• 2016

This paper presents a mathematical model for optimizing earthwork allocation plan that minimizes earthwork cost. The model takes into account operational constraints in the real-world earthwork such as material-type (i.e., quality level of material) and quantities excavated from cut-sections, required quality of material and quantities for each embankment layer, top-down cutting and bottom-up filling constraints, and allocation orders. These constraints are successfully handled by assuming the rock-earth material as the three dimensional (3D) blocks. The study is of value to project scheduler because the model identifies the optimal earth allocation plan (i.e., haul direction (cut and fill pairs), quantities of soil, type of material, and order of allocations) expeditiously and is developed as an automated system for usability. It is also relevant to estimator in that it computes more realistic earthworks costs estimation. The economic impact and validity of the mathematical model was confirmed by performing test cases.

• Journal of the Korean Data and Information Science Society
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• v.21 no.2
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• pp.355-361
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• 2010

This paper addresses a mathematical approach to decision making in a real-world material distribution situation. The problem is characterized by a low-volume and highly-varied mix of products, therefore there is a lot of material movement between the facilities. This study focuses especially on the transportation scheduler with a tool that can be used to quantitatively analyze the volume of material moved, the type of truck to be used, production schedules, and due dates. In this research, we have developed a mixed integer programming problem using the minimum cost, multiperiod, multi-commodity network flow approach that minimizes the overall material movement costs. The results suggest that the optimization approach provides a set of feasible solution routes with the objective of reducing the overall fleet cost.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.267-276
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• 2022

Modelling the energy release performance of energetic material combustion in closed systems is of fundamental importance for aerospace and defense application. In particular, to compensate for the disadvantage of the combustion of single energetic material and maximize the benefits, a method of combusting the mixed energetic materials is used. However, since complicated heat transfer occurs when the energetic material is combusted, it is difficult to theoretically predict the combustion performance. Here, we suggest a theoretical model to estimate the energy release performance of mixed energetic material based on the model for the combustion performance of single energetic material. To confirm the effect of parameters on the model, and to gain insights into the combustion characteristics of the energetic material, we studied parameter analysis on the reaction temperature and the characteristic time scales of energy generation and loss. To validate the model, model predictions for mixed energetic materials are compared to experimental results depending on the amount and type of energetic material. The comparison showed little difference in maximum pressure and the reliability of the model was validated. Finally, we hope that the suggested model can predict the energy release performance of single or mixed energetic material for various types of materials, as well as the energetic materials used for validation.

• Communications of the Korean Mathematical Society
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• v.20 no.3
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• pp.589-602
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• 2005

We present the numerical algorithm for the model for high-strain rate deformation in hyperelastic-viscoplastic materials based on a fully conservative Eulerian formulation by Plohr and Sharp. We use a hyperelastic equation of state and the modified Steinberg and Lund's rate dependent plasticity model for plasticity. A two-dimensional approximate Riemann solver is constructed in an unsplit manner to resolve the complex wave structure and combined with the second order TVD flux. Numerical results are also presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.707-710
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• 2000

Optimization of the biphenyl chloromethylation process with para-formaldehyde has been investigated in the presence of ZnCl$_2$with HCI gas by the Box-Wilson method of mathematical planning of experiment. The 4,4'- (dichloromethyl)-biphenyl yield dependence on the biphenyl para-formaldehyde ratio, temperature and reaction duration has been studied. A mathematical model of the process has been developed and optimal conditions for the biphenyl chloromethylation procedure has been determined.

• Education of Primary School Mathematics
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• v.9 no.2 s.18
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• pp.89-105
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• 2005

The purposes of this study were to develop an effective teaching material for slow learners in mathematics and to investigate its effect. To achieve the first goal, several pre-used teaching material and the 7th national curriculum for elementary school mathematics were analyzed to set up a framework fur developing new teaching material. Using these developed framework and curriculum data, 370 units of lesson were developed from the 3rd grade to the 6th grade. To investigate the effect of the material, 3 slow learners (2 from the 5th and 1 from the 6th grade) were selected through diagnostic tests. Then supplementary lessons were administered after school to relieve their disability accordingly for seven months. During the lessons(lasted about 40 minutes), teacher observed the subjects in detail and .judged the teaming sequence and the learning pace. Through this observation and the test administered after the treatment, several conclusions were drawn as follow: First, the supplementary lessons using the developed teaching material helped slow learners understand mathematics and solve problems. Especially, the test scores gained on formative evaluation became higher. This might be caused by the material that enabled to relieve the disablement and the teaching method that aimed to give a meaningful mathematical experience. Second, the supplementary lessons affected positively to the affective domain of the slow learners. They convinced themselves to their mathematical ability and became active in their mathematics class. This was observed by researcher and the class teacher in their lessons. Positive attitude toward mathematics and their ability is quite important for mathematics learning especially fur slow learners in mathematics.

• Research in Mathematical Education
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• v.22 no.3
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• pp.223-243
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• 2019

Researchers have been attending to the potential of curriculum materials as resources for professional development. In order for a curriculum material to fulfil such purpose, curriculum authors should intentionally attend to educativeness of the material. A feature of educative material is that its voice speaks to teachers. In this study, I explore educativeness of Algebra teacher guides by attending to their voice. In particular, I focused on the use of pronouns, modality, and imperatives. Findings indicate that some teacher guides have more educative voice than the others and that the amount each guide talk to teachers were less than sufficient. Implications for future research and practice are discussed.

• Steel and Composite Structures
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• v.48 no.5
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• pp.583-597
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• 2023

This paper introduces a novel approach to multi-material topology optimization (MTO) targeting in-plane bi-directional functionally graded (IBFG) non-uniform thickness Reissner-Mindlin plates, employing an alternative active phase approach. The mathematical formulation integrates a first shear deformation theory (FSDT) to address compliance minimization as the objective function. Through an alternating active-phase algorithm in conjunction with the block Gauss-Seidel method, the study transforms a multi-phase topology optimization challenge with multi-volume fraction constraints into multiple binary phase sub-problems, each with a single volume fraction constraint. The investigation focuses on IBFG materials that incorporate adequate local bulk and shear moduli to enhance the precision of material interactions. Furthermore, the well-established mixed interpolation of tensorial components 4-node elements (MITC4) is harnessed to tackle shear-locking issues inherent in thin plate models. The study meticulously presents detailed mathematical formulations for IBFG plates in the MTO framework, underscored by numerous numerical examples demonstrating the method's efficiency and reliability.

• Journal of the Korean School Mathematics Society
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• v.12 no.3
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• pp.291-305
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• 2009

The purpose of this article is to formulate the base that mathematical thinking power can be improved through activating the metacognitive ability of students in the math problem solving process. The guidance material for activating the metacognitive ability was devised based on a body of literature and various studies. Two high school students used it in their math problem solving process. They reported that their own mathematical thinking power was improved in this process. And they showed that the necessary strategies and procedures for math problem solving can be monitored and controled by analyzing their own metacognition in the mathematical thinking process. This result suggests that students' metacognition does play an important role in the mathematical thinking process.