• Journal of the Semiconductor & Display Technology
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• v.16 no.4
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• pp.46-51
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• 2017

Recent controller design techniques often discretize the target system and implement a discrete controller that is digitized to match the target system. When constructing such a discrete system, it is necessary to first determine the sampling time. The smaller the sampling time is, the more advantageous it can be made similar to the original system, but the cost is a problem when realizing such a configuration as hardware. On the other hand, the longer the time, the more different the system is from the original system, and eventually the control becomes impossible. In this paper, we consider the above problem and propose a more logical approach to determine the sampling time in the discrete system and investigate the relation with the differential controller. We also apply this process to a nonlinear system called ARAGO disc and verify its validity through computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.819-824
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• 1989

This paper proposes a new method for the discovery and design of an optimal heat exchanger network. The method is based upon the concept of pinch, a problem reduction technique and the heuristics developed in this work. It generates subproblems in a logical way and solves the subproblems by the heuristics to synthesize an optimal network structure. It is thought that the heuristics can preserve the minimum utility consumption, the minimum number of heat exchanger units, and the minimum number of stream splittings needed for a given problem. The minimum heat exchanger area for the optimal network can then be obtained by adjusting the temperatures associate with the heat exchanger in the optimal network structure. The method is applied to the problems appeared in the literatures. The results show the reductions in the number of heat exchanger units for some problems.

• Journal of The Korean Association For Science Education
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• v.17 no.3
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• pp.313-321
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• 1997

The purpose of this study was to investigate the instructional effect of a four-stage problem solving approach visually emphasizing the molecular level of matter upon students' conceptions and problem solving ability. On the basis of the research results regarding molecular representation in learning chemistry, problem-solving instruction, and the effect of visual materials, the instructional strategy was developed while considering Korean educational situations. The treatment and control groups (2 classes) were selected from a girls' high school in Seoul and taught about stoichiometry, gas, liquid, solid, and solution for 13 weeks. For the treatment group, 52 charts were supplied in order to emphasize the molecular level of matter and/or 4 stage problem solving strategy-understanding, planning, solving, and reviewing. For the control group, traditional instruction was used. Before the instructions, the Group Assessment of Logical Thinking and the Spatial Ability Test were administered, and their scores were used as covariate and blocking variable, respectively. After the instructions, students' conceptions and problem solving ability were measured by the Chemistry Conceptions Test (CCT) and the Chemistry Problem Solving Ability Test (CPSAT), respectively. The results indicated that the CCT scores of the treatment group were significantly higher than those of the control group. The students in the treatment group also exhibited less misconceptions than those in the control group. However, there was not significant difference for the CPSAT scores. No interaction with students' spatial ability was found for both students' conceptions and problem solving ability. Educational implications are discussed.

• The Journal of Korean Association of Computer Education
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• v.19 no.1
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• pp.27-39
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• 2016

It is necessary for us to be equipped with problem-solving ability, logical thinking ability, and convergence thinking ability in the digital information age. To have these abilities, modern people in the $21^{st}$ century should be educated to develop the computational thinking ability. However, it is difficult to cultivate the computational thinking ability in current computer education curriculum. Therefore, this paper aims to propose a programming-based computer educational program to make students better understand the principles of computer science and enhance student's computational thinking ability escaping from current fragmentary and limited computer education. In order to verify the effectiveness of the educational program, students in total 42 middle school (22 students in 1st and 2nd grades and 20 in 3rd grade) were applied to the educational program for twenty-four hours on 12 weeks and then we obtained a positive result that might bring improvement on the logical thinking ability and creative problem-solving skills. As a result, this study presents the possibility of its field applications of computational thinking-based programming learning and analyzed the effectiveness. therefore, it has a notable point of presenting the development direction of a variety of education programs for enhancing the computational thinking in the future.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.4
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• pp.563-581
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• 2016

Studies on meta-affect in problem solving tried to build similar structures among affective elements as the structure of cognition and meta-cognition. But it's still need to be more systematic as meta-cognition. This study defines meta-affect as the connection of cognitive elements and affective elements which always include at least one affective element. We logically categorized types of meta-affect in problem solving, and then observed and analyzed the real cases for each type of meta-affect based on the logical categories. We found the operating mechanism of meta-affect in mathematical problem solving. In particular, we found the characteristics of meta function which operates in the process of problem solving. Finally, this study contributes in efficient analysis of meta-affect in problem solving and educational implications of meta-affect in teaching and learning in problem solving.

• Journal of Gifted/Talented Education
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• v.21 no.3
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• pp.703-718
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• 2011

Team-Based Learning can play an important role in gifted education, because that improve decision making, coordination and problem-solving ability through shapely team activity. So, when a program that founded on Team-Based Learning applied to gifted students, investigated the improved effects of creative problem solving ability. Developed programs consisted of total 10 times and were conducted the lesson for 13student (male 3, female 10) of 4, 5th grade gifted students class in S elementary school, Sancheong-gun. The improved effects of creative problem solving ability were selected as the self-checking tool of creative problem-solving ability. Due to a small number of students, nonparametric test has done with the results of before and after, it showed significantly improvements in significance level of 5%. In particular, there was a significant improvement in the field of divergent thinking, critical logical thinking. Therefore, the programs based on Team-Based Learning are effective for enhance creative problem solving ability of gifted students, they will be used widely in the classroom to require creative problem solving ability or the acquisition of knowledge of gifted students.

• Journal of the Korean Chemical Society
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• v.64 no.1
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• pp.19-29
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• 2020

We analyzed the representations of acid-base models in 4 kinds of Chemistry I and 4 kinds of Chemistry II textbooks of the 2009 revised curriculum, and 9 kinds of Chemistry I textbooks and 6 kinds of chemistry II textbooks of the 2015 revised curriculum in this study. The problems of the textbook were divided into the problems of definitions and the representations of the logical thinking. As a result of the study, the lack of the concept of chemical equilibrium had a problem with the representation of reversible reactions in the definition of the Brønsted-Lowry model in the Chemistry I textbooks of 2009 revised curriculum, it also appeared to persist in Chemistry I textbooks of 2015 revised curriculum which contains the concept of chemical equilibrium. The representations of logical thinking were related to particle kinds of conservation logic, combinational logic, particle number conservation logic, and proportion logic. There were few problems related to representation of logical thinking in Chemistry I textbook in 2009 revision curriculum, but more problems of representations related to logics are presented in Chemistry I textbooks in 2015 revision curriculum. Therefore, as the curriculum is revised, the representations of chemistry textbooks related to acid and base models need to be changed in a way that can help students' understanding.

• Journal of the Korean School Mathematics Society
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• v.16 no.4
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• pp.797-820
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• 2013

This study intended on analyzing the error patterns of mathematic problem posing sentences by the 100 elementary pre-teachers and discussing about the solutions. The results showed that the problem posing sentences have five error patterns: phonological error patterns, word error patterns, sentence error patterns, meaning error patterns, and notation error patterns. Divided into fourteen specific error patterns, they are as in the following. 1) Phonological error patterns are consisted of the 'ㄹ' addition error pattern and the abbreviated word error pattern. 2) Words error patterns are divided with the inappropriate usage of word error pattern and the inadequate abbreviation error pattern, which are formulized four subgroups such as the case maker, ending of the word, inappropriate usage of word, and inadequate abbreviation of article or word error pattern in detail. 3) Sentence error patterns are assumed four kinds of forms: the reference, ellipsis of sentence component, word order, and incomplete sentence error pattern. 4) Meaning error patterns are composed the logical contradiction and the ambiguous meaning. 5) Notation error patterns are formed four patterns as the spacing, punctuation, orthography of Hangul, and spelling rules of foreign words in Korean. Furthermore, the solutions for these error patterns were discussed: First, it has to be perceived the differences between spoken and written language. Second, it has to be rejected the spoken expressions in written contexts. Third, it should be focused on the learning of the basic sentence patterns during the class. Forth, it is suggested that the word meaning should have the logical development perception based on what it means. Finally, it is proposed that the system of spelling of Korean has to be learned. In addition to these suggestions, a new understanding is necessary regarding writing education for college students.

• 한국정보교육학회:학술대회논문집
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• 2010.08a
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• pp.235-241
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• 2010

This paper has been studied about algorithm teaching methods for improving the problem-solving skills and creativity in rapidly changing information society. Especially the algorithms for teaching about computer is very important. Because it is effective learning content for finding the best solution to solve a problem and improve the students' logical thinking. However, teaching algorithms can be monotonous to children on account of using only computer and languages. So It needs to consider about the cognitive structure and level of elementary school students. Therefore, this study has the purpose to acquaint students with the principle of algorithm and improve problem-solving and creativity using games, not computer.

• Journal of the Korea Society of Computer and Information
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• v.20 no.11
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• pp.191-197
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• 2015

Recently, it has been activated the software education or coding education for the improvement of the Computational Thinking (CT) ability at home and abroad. Also the CT has influence on courses of Computer Science in the college levels. It has been introduced and the number of cases of using it to general K12 education has increased. However, the research on the software education's influence on the CT was still lacking. So In this paper, we proposed this study has been conducted on how Scratch education in the elementary school level influenced the ability of the CT. And we proposed software education can improve the ability of CT. First, we provided the theoretical base of the software education and evaluation process through analysis of computational thinking ability. A core analysis content of the CT is broader than algorithmic thinking and can be achieved without using computer. It includes abstract, algorithmic, logical, and measurable thinking. Second, we made efforts to improve the characteristics of the software education with categorization. Finally, we have managed the software education using Picoboard with Scratch and flowchart within 15 weeks based on these theocratical research. An examination of the effectiveness was committed to understand, analyze, and develop strategies of problem solving. It is designed as a strategy of problem solving before and after the software lesson. The result of the software education has improved authentically in all areas without the need to design a strategy for problem solving.