• School Mathematics
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• v.10 no.3
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• pp.423-441
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• 2008

The purpose of this study was to examine the Pedagogical Content Knowledge(PCK) of teachers and their educational practice in the category of plane figure, to make a comparative analysis of their PCK and educational practice, and to discuss the relationship between their PCK and the characteristics of their instruction. Instruction of four selected elementary school teachers was analyzed to find out their educational practice. In conclusion, the characteristics of the PCK and actual instruction of the teachers could be listed as below: First, as a result of comparing their PCK and educational practice on plane figure by applying selected analysis criteria, there was a close correlation between their PCK and actual instruction. Second, the teachers had various levels of PCK on different areas. Especially, there was a large disparity in mathematical content knowledge and knowledge of teaching methods. Third, the teachers who had plenty of PCK were more excellent in textbook reconstructing, and those who fell behind in terms of PCK were more reliant on textbooks as if the textbooks had been the Bible.

• Communications of Mathematical Education
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• v.38 no.2
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• pp.215-230
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• 2024

Congruences and symmetry are familiar concepts that can be encountered in everyday life. In order to effectively understand and acquire these concepts, the role of appropriate visual examples is important. This analysis examined various visual examples used in the process of learning the concepts of congruence and symmetry in elementary mathematics textbooks and focused on the use of convex polygons and concave polygons. As a result of the analysis, various types of polygons were used as visual examples for teaching and learning of congruence and symmetry in textbooks. The frequency of use of concave polygons was higher in the order of congruence, line symmetry, and point symmetry, and it was confirmed that it was used more frequently in the process of exploring properties than in the introduction of the concept. Based on these results, a plan to utilize concave polygons in teaching and learning of congruence and symmetry was sought.

• Journal of Elementary Mathematics Education in Korea
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• v.15 no.2
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• pp.361-383
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• 2011

This study is on teaching about the areas of plane figures through open instruction, which aims to discover the pedagogical meanings and implications in the application of open methods to math classes by running the Math A & B classes regarding the areas of parallelogram, triangle, trapezoid and rhombus for fifth graders of elementary school through open instruction method and analyzing the educational process. This study led to the following results. First, it is most important to choose proper open-end questions for classes on open instruction methods. Teachers should focus on the roles of educational assistants and mediators in the communication among students. Second, teachers need to make lists of anticipated responses from students to lead them to discuss and focus on more valuable methods. Third, it is efficient to provide more individual tutoring sessions for the students of low educational level as the classes on open instruction methods are carried on. Fourth, students sometimes figured out more advanced solutions by justifying their solutions with explanations through discussions in the group sessions and regular classes. Fifth, most of students were found out to be much interested in the process of thinking and figuring out solutions through presentations and questions in classes and find it difficult to describe their thoughts.

• Education of Primary School Mathematics
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• v.11 no.2
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• pp.141-159
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• 2008

The purpose of this study id to delve into how elementary mathematics textbook deal with the quadrilaterals from a view of Didactic Transposition Theory. Concerning the instruction period and order, we have concluded the following: First, the instruction period and order of quadrilaterals were systemized when the system of Euclidian geometry was introduced, and have been modified a little bit since then, considering the psychological condition of students. Concerning the definition and presentation methods of quadrangles, we have concluded the following: First, starting from a mere introduction of shape, the definition have gradually formed academic system, as the requirements and systemicity were taken into consideration. Second, when presenting and introducing the definition, quadrilaterals were connected to real life. Concerning the contents and methods of instruction, we have concluded the following: First, the subject of learning has changed from textbook and teachers to students. Second, when presenting and introducing the definition, quadrilaterals were connected to real life. Third, when instructing the characteristics and inclusive relation, students could build up their knowledge by themselves, by questions and concrete operational activities. Fourth, constructions were aimed at understanding of the definition and characteristics of the figures, rather than at itself.

• School Mathematics
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• v.15 no.4
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• pp.667-682
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• 2013

Though teachers' lesson plays, this article analysed teachers' knowledge for mathematical teaching about mathematical definitions and their pedagogical difficulties in teaching defining. Although the participant teachers didn't transmit definitions to students and suggested possible definitions of the given geometric figure in their imaginary lessons, they didn't teach defining as deductive organization of properties of the geometric figure. They considered mathematical definition as a mere linguistic convention of a word, so they couldn't appreciate the necessity of deductive organization in teaching definitions, and the arbitrary nature of mathematical definitions. Therefore, for learning to teach definitions differently, it is necessary for teachers to reflect the gap between the everyday and mathematical definitions in teachers'education.

• Korean Journal of Cognitive Science
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• v.15 no.2
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• pp.17-22
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• 2004

Two experiments were executed to investigate the effect of uniform connectedness systematically using the identification task of briefly exposed forms. Previous study observed negative repetition effected (i.e., NRE) in the identification task of two parentheses either connected or disconnected vertically, which was interpreted as an evidence against the hypothesis of uniform connectedness. Experiment I tested the hypothesis that NRE resulted from the Perceptual set or anticipating disconnected displays. Experiment 2 tested the hypothesis that NRE resulted from relatively shorter exposure time. Using partial report task asking participants to report only the cued target and whole report task asking them to report the whole pattern with only connected displays, experiment 1 observed NRE respectively. Experiment 2, with longer exposure time equivalent to 83% accuracy and response bias controlled by use of catch trials, obtained the same NRE. Those results seems to indicate that uniformly connected forms were processed analytically by perceivers without task demand and futhermore, the hypothesis of uniform connectedness as a principle of perceptual organization is not plausible.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.4
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• pp.521-526
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• 2012

The performance of arrow from a manufacturing process depends on arrow's trajectory(archer's paradox) and intensity of an impact points. Especially, when conducting a shooting experiment over and over in the same experiment condition, the intensity of impact point is an objective standard to judge the performance of the arrow. However, the analysis method for the impact point is not enough, a previous research of the arrow's performance has been focused on a skill to optimize a manufacturing variables(feathers of an arrow, barb of an arrow, arrow's shaft, weight, external diameter, spine). In this paper, We propose measurement system of arrow's impact point with Mamdani fuzzy inference system and similarity of polygon for automation of impact point's measurement. Measuring the impact point data of the arrow moving with a high speed(approximately 275km/h) by using line laser and photo diode array, then the measured data are mapped to arrow's impact point with fuzzy inference and similarity of polygon.

• Journal of architectural history
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• v.17 no.3
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• pp.23-43
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• 2008

Seoul has been watched at its symbolic image which is the capital of one nation. since then Joseon was established. So, most of study about Seoul placed too much emphasis on like next; urban organization, palace, government office and public establishment. On the other hand, it is lacking in study of the individual building, the residential district, the change of building-lot. This study is to make up a deficiency from study of Gaokdohyung(家屋圖形site and floor plan). Gaokdohyung(家屋圖形) is drawings of building lots & houses existed in Hanseongbu漢城府(modem Seoul). It is possessed in Jangseogak and all 24 sheets. It is merely 24sheets but has many urban information in that. Housing of number 116 expressed in Gaokdohyung are consist on the house of Sadaebu士天王(noble class) Joongin中人(middle class) Sangmin常民(commoner), Villa(Byeolseo別墅) and connecting stores etc. Houses in Gaokdohyung has characteristic that most building lot is very specious and owners are variety of social position. The study of Gaokdohyung will progress through analyzing diachronic change of individual building lot & house. In the event, results of this study will help to find out change of urban tissue & architecture. So, i intend to seek for entity of urban tissue and urban house in Joseon Period differ from now, and to study out those have been changed continuously forward now.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.155-164
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• 2005

Volcanic rocks from the Mt. Mudeung area which are composed of Hwasun andesite, Mudeungsan dacite and Togok rhyolite contain plagioclase phenocrysts in common. Majority of the repeated twins observed in optical microscopy are albite twin and some are pericline twin. EPMA studies of plagioclases from Hwansun andesite, Mudeungsan dacite and Togok rhyolte indicate calcic andesine, andesine-oligoclase, nearly pure albite, respectively Albite twin and pericline twin can be easily distinguished through TEM diffraction patterns, which is quite difficult by optical microscopy. Plagioclases in volcanic rocks from the Mt. Mudeung area do not show e-reflection in (100) electron diffraction patterns, probably because of their high cooling rate, which inhibited phase separations during cooling.

• Journal of Korean Society for Geospatial Information Science
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• v.5 no.1 s.9
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• pp.103-118
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• 1997

In recent years, there have been emerging the establishment and extension of sewage treatment facilities in many cities due to population growth and high standard for sewage treatment. The objective of this study is to develop and implement a Data Management Library which could deal with enormous amount of graphic and attribute data effectively and afficiently. Based on the Data Management Library developed, the Sewage Treatment Management System(STMS) was Implemented and investigated in preparation for the extension of sewage treatment facilities. Cheongju city enviromental station was selected as a test site. We first analyzed current work flow in sewage treatment and then performed database design suitable for managing sewage treatment in effective fashion. The STMS consists mainly of two parts : one is for manipulating the graphic and attribute data and the other for application of sewage treatment related works. Conclusively, the STMS developed in this study could be utilized as a comer stone for an effective maintenance and management of sewage treatment.