• Journal of the Korean School Mathematics Society
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• v.16 no.4
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• pp.719-743
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• 2013

Proportional reasoning is considered as a difficult concept to most elementary school students and might be connect to functional thinking, algebraic thinking, and mathematical thinking later. The purpose of this study is to analyze the sixth graders' development level of proportional reasoning so that children's problem solving processes on different proportional problem items were investigated in a way how the problem type of proportion and the degree of ill-structured affect to their levels. Results showed that the greater part of participants solved problems on the level of proportional reasoning and various development levels according to type of problem. In addition, they showed highly the level of transition and proportional reasoning on missing value problems rather than numerical comparison problems.

• Journal of the Korean School Mathematics Society
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• v.16 no.1
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• pp.63-86
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• 2013

This study aimed to explore how middle school students perceive constructed-response items and how they solve those items and the patterns of the processes. For this purpose, data were collected from middle school students through survey, written responses on those items that were developed for this particular purpose, and interviews. The survey data were analyzed by using Excel and the written responses and interview data qualitatively. The findings about the students' perceptions about the constructed-response items suggested that the middle school students perceive the items primarily as involving writing solutions logically(17%) and being capable of explaining while solving them(7%). The most difficulties they encounter when solving the items were understanding(26%), applying(12%), mathematical writing(25%), computing(23%), and reasoning(14%). The findings about the students' mathematical proficiencies showed that they made an error most in reasoning (35%), then in understanding(31%), in applying(9%), and least in computing(3%).

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.448-451
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• 2000

Fuzzy control has been researched for application of industrial processes which have no accurate mathematical model and could not controlled by conventional methods because of a lack of quantitative input-output data. Intelligent control approach based on fuzzy logic could directly reflex human thinking and natural language to controller comparing with conventional methods. In this paper, the tested system is constructed for sending a ball to the goal position using wind from two DC motors in the path. This system contains non-linearity and uncertainty because of the characteristic of aerodynamics inside the path. The system used in this experiment could be hardly modeled by mathematic methods and could not be easily controlled by linear control manners. The controller, in this paper could control the system containing non-linearity and uncertainty because it is designed based on the input-output data and experimental knowledge obtained by trials.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2296-2298
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• 2000

Fuzzy control has been researched for application of industrial processes which have no accurate mathematical model and could not controlled by conventional methods because of a lack of quantitative input-output data. Intelligent control approach based on fuzzy logic could directly reflex human thinking and natural language to controller comparing with conventional methods. In this paper, fuzzy controller is implemented to acquire operator's knowledge. The tested system is constructed for sending a ball to the goal position using wind from two DC motors in the path. This system contains non-linearity and uncertainty because of the characteristic of aerodynamics inside the path. Ball position is measured by a vision camera. The system used in this experiment could be hardly modeled by mathematic methods and could not be easily controlled by linear control manners. The controller, in this paper is designed based on the input-output data and experimental knowledge obtained by trials.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2096-2098
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• 2001

Fuzzy control has been researched for application of industrial processes which have no accurate mathematical model and could not be controlled by conventional methods because of a lack of quantitative input-output data. Intelligent control approach based on fuzzy logic could directly reflex human thinking and natural language to controller comparing with conventional methods. In this paper, the tested system is constructed for sending a ball to the goal position using wind from two DC motors in the path. This system contains non-linearity and uncertainty because of the characteristic of aerodynamics inside the path. The system used in this experiment could be hardly modeled by mathematic methods and could not be easily controlled by linear control manners. The controller, in this paper could control the system containing non-linearity and uncertainty.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.603-610
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• 2001

Industrial processes are normally operated by skilled humans who have the cumulative and logical information about the system. Fuzzy control has been investigated for many application. Intelligent control approaches based on fuzzy logic have a chance to include human thinking. This paper represents modeling approach based upon operators knowledge without mathematical model of the system and optimize the controller. The experimented system is constructed for sending a ball to the goal position using wind of two DC motors in the predefined path. A vision camera to mimic human eyes detects the ball position. The system used in this experiment could be hardly modeled by mathematical methods and ould not be easily controlled by conventional manners. The controller is designed based on the input-output data and experimental knowledge obtained by trials, and optimized under the predefined performance criterion. And this paper shows the data adaptation for changeable operating condition. When the system is driven in the abnormal condition with unconsidered noise, the new optimal operating parameters could be defined by adjusting membership functions. Thus, this technique could be applied in industrial fields.

• School Mathematics
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• v.5 no.4
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• pp.541-553
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• 2003

The purposes of this study are to look into the changing processes of mathematical beliefs and attitudes of the students and to propose the plans how to manage cooperative learning, what can contribute to cognitive affective domains of mathematics learning in applying STAD-based cooperative loaming to mathematics class. So we, the researchers performed cooperative learning in the fifth grade of elementary school and did the exams of mathematical beliefs and attitudes, interviews, supplementary Questions. And students showed meaningful changes in 'the need of cooperative learning', 'critical thinking', 'the acceptance of thoughts of others'. Meanwhile, there were possibilities what all the members of one group can't recognize their errors in STAD, so we proposed 'Tongsinsa'. And we presented concrete methods how to reconstruct groups and somethings to consider when students are not satisfied with the group activities.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.241-250
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• 2020

In this paper, we propose a direction of teaching method for future generations. In order to suggest such the direction, teaching and learning materials that integrate coding activities and mathematical modeling were developed through top-down and bottom-up processes. Coding and engineering experts and mathematics education experts developed teaching and learning materials through councils (top-down courses) and applied them to 24 high school first graders based on student responses (bottom-up courses). Additionally, the developed curriculum helped students increase interest and motivation and realize conceptual understanding, problem posing, and problem solving in mathematics. On the basis of these results, it provided an idea about how to develop curriculum combining mathematical modeling with coding activities, needed for the fourth industrial revolution.

• Communications of Mathematical Education
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• v.33 no.4
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• pp.425-444
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• 2019

Comparing to the U.S. mathematics textbooks, this study examines the opportunity to learn statistical processes represented in mathematics textbooks reflecting 2015 revised curriculum. Analyzing four different kinds of Korean middle school mathematics textbooks and two kinds of corresponding U.S. textbooks for seventh graders, we found that the tasks dealing with all the phases of statistical processes were found only in the U.S. textbooks while not even one task in such a case was not observed in the Korean textbooks. To make matters worse, the proportion of the tasks dealing with only one phase of statistical processes was 93.3% of all the tasks in Korean textbooks. In terms of types of tasks, the types of tasks were very homogeneous in Korean textbooks, usually Types FPR or PR while more various types of tasks were found in the U.S. textbooks such as Types FRI, PRI, FR, or RI. In views of features of each phase in statistical processes, Korean textbooks heavily focused only on some particular statistical behaviors such as 'formulating a problem', 'collecting data', 'transforming data', and 'analyzing a part of data.' The findings of this study provide meaningful implications for improving statistics education and developing mathematics textbooks to enhance students' statistical thinking and problem-solving ability.

• Journal of Educational Research in Mathematics
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• v.15 no.3
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• pp.251-272
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• 2005

Given that cognitive demands of mathematical tasks can be changed during instruction, this study attempts to provide a detailed description to explore how tasks are set up and implemented in the classroom and what are the classroom-based factors. As an exploratory and qualitative case study, 4 of six-grade classrooms where high-level tasks on ratio and proportion were used were videotaped and analyzed with regard to the patterns emerged during the task setup and implementation. With regard to 16 tasks, four kinds of Patterns emerged: (a) maintenance of high-level cognitive demands (7 tasks), (b) decline into the procedure without connection to the meaning (1 task), (c) decline into unsystematic exploration (2 tasks), and (d) decline into not-sufficient exploration (6 tasks), which means that the only partial meaning of a given task is addressed. The 4th pattern is particularly significant, mainly because previous studies have not identified. Contributing factors to this pattern include private-learning without reasonable explanation, well-performed model presented at the beginning of a lesson, and mathematical concepts which are not clear in the textbook. On the one hand, factors associated with the maintenance of high-level cognitive demands include Improvising a task based on students' for knowledge, scaffolding of students' thinking, encouraging students to justify and explain their reasoning, using group-activity appropriately, and rethinking the solution processes. On the other hand, factors associated with the decline of high-level cognitive demands include too much or too little time, inappropriateness of a task for given students, little interest in high-level thinking process, and emphasis on the correct answer in place of its meaning. These factors may urge teachers to be sensitive of what should be focused during their teaching practices to keep the high-level cognitive demands. To emphasize, cognitive demands are fixed neither by the task nor by the teacher. So, we need to study them in the process of teaching and learning.