• Education of Primary School Mathematics
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• v.12 no.1
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• pp.39-55
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• 2009

For this study, the 'Game Activities' lessons presented in the math textbooks from the 1st grade to the 6th were examined in terms of learning materials, the learning members' make-up, the playing structures, and the relation with the contents. In addition, the survey by means of questionnaires was conducted to analyze the actual condition of teachers' guidance in the field. The findings from this research were as follows: First, as for the activities presented in the textbooks, it turned out that too much emphasis is placed upon plays mainly using learning materials such as cards and dice played by teams of two. In addition, there have been shown negative aspects in various ways of plays putting too much emphasis on certain types of plays such as and structures. As for the relation with the contents, although lots of efforts were taken to connect the playing activity to the lesson contents, there were units presenting plays based on the preceding lesson's repeated activity, ones that have weak link with the contents. Second, it turned out that the teachers had negative attitude on the guidance using the 'Game Activities' lesson, although they were aware of the effects of playing in math learning. This seemed to result from the delicate variety and insufficient preparation for the play. Besides, the findings indicate that the appreciation and activity of the 'Game Activities' lesson presented as a way of performance evaluation. for play need to be provided in school or classrooms for teachers and students to make good use of them.

• Education of Primary School Mathematics
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• v.17 no.2
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• pp.127-157
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• 2014

The purpose of the study is to enhance the figure analysis ability for pre-service elementary teacher by using GSP. To do this, we limited to teaching competence divide into ability various problem-solving, extract key elements, predict the difficulty of student and investigated the initial of them, the reality of GSP construction. As results, pre-service elementary teachers made errors, proposed teaching focused on the character using in the problem solving, and found that in one particular difficulties to find the students. The reality of GSP construction activity was possible to explore through the partially constructed a number of various properties, but we found to have difficulty in the connection between concepts. and integrated view of the problem analysis. After visual identification and exploration through the GSP construction, problem-solving ability became a little more variety and changed their direction in order to focus the student's anticipated difficulties. From these results, we could extract some pedagogical implications helping pre-service teachers to reinforce teaching competence by GSP construction.

• Education of Primary School Mathematics
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• v.17 no.2
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• pp.95-111
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• 2014

The purpose of this study is to determine the relationship between metacognition and math creative problem solving ability. Specific research questions set up according to the purpose of this study are as follows. First, what relation does metacognition has with creative math problem-solving ability of mathematically gifted elementary students? Second, how does each component of metacognition (i.e. metacognitive knowledge, metacognitive regulation, metacognitive experiences) influences the math creative problem solving ability of mathematically gifted elementary students? The present study was conducted with a total of 80 fifth grade mathematically gifted elementary students. For assessment tools, the study used the Math Creative Problem Solving Ability Test and the Metacognition Test. Analyses of collected data involved descriptive statistics, computation of Pearson's product moment correlation coefficient, and multiple regression analysis by using the SPSS Statistics 20. The findings from the study were as follows. First, a great deal of variability between individuals was found in math creative problem solving ability and metacognition even within the group of mathematically gifted elementary students. Second, significant correlation was found between math creative problem solving ability and metacognition. Third, according to multiple regression analysis of math creative problem solving ability by component of metacognition, it was found that metacognitive knowledge is the metacognitive component that relatively has the greatest effect on overall math creative problem-solving ability. Fourth, results indicated that metacognitive knowledge has the greatest effect on fluency and originality among subelements of math creative problem solving ability, while metacognitive regulation has the greatest effect on flexibility. It was found that metacognitive experiences relatively has little effect on math creative problem solving ability. This findings suggests the possibility of metacognitive approach in math gifted curricula and programs for cultivating mathematically gifted students' math creative problem-solving ability.

• School Mathematics
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• v.6 no.1
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• pp.59-90
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• 2004

This study has been established with two purposes. The first one is to development the learning-teaching model for enhancing students' creative proof capacities in the domain of demonstrative geometry as subject content. The second one is to aim at experimentally testing its effectiveness. First, we develop the learning-teaching model for enhancing students' proof capacities. This model is named the generative-convergent model based instruction. It consists of the following components: warming-up activities, generative activities, convergent activities, reflective discussion, other high quality resources etc. Second, to investigate the effects of the generative-convergent model based instruction, 160 8th-grade students are selected and are assigned to experimental and control groups. We focused that the generative-convergent model based instruction would be more effective than the traditional teaching method for improving middle school students' proof-writing capacities and error remediation. In conclusion, the generative-convergent model based instruction would be useful for improving middle grade students' proof-writing capacities. We suggest the following: first, it is required to refine the generative-convergent model for enhancing proof-problem solving capacities; second, it is also required to develop teaching materials in the generative-convergent model based instruction.

• Tunnel and Underground Space
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• v.26 no.5
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• pp.363-374
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• 2016

All five independent elastic constants of a transversely isotropic rock sometimes need to be determined from a single specimen. Saint-Venant approximation has been widely used for a long time in the analysis of single specimen test. This paper has proven how this empirical equation can be mathematically transformed into a form of the apparent Young's modulus based on theory of elasticity. The transformed equation is a monotonous function on anisotropic angle and can be useful in the analysis of the in-situ stress measurement in an anisotropic rock mass. The estimations of data in literatures have shown that the measured values of $G^2$ are uniform on anisotropic angles and smaller than that of Saint-Venant's case. This decrement may be caused by sliding of the interface of strata and the decrement rate is inferred to relate well with the combination of bonding condition of strata and strength of rock material. Accumulation of these kinds of studies in the future enables to define the decrement and to determine elastic constants of a transversely isotropic rock from a single specimen from modifying Saint-Venant approximation.

• 대한공업교육학회지
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• v.37 no.1
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• pp.125-143
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• 2012

This study aimed to identify the effect of the instruction applied with a project method for the 'Making Model by Architecture' unit in vocational High schools on the improvement of the Key competences. With this aim, the study selected as an experimental group, control group third graders in two classroom in G vocational High Schools in Goyang, Gyeonggi-do. Aiming at the selected students in the experimental group and the control group, the study conducted a pre-test of their Key competences; thus, the study confirmed that there was no statistically significant difference. Then, the study offered a class applied with a project method to the experimental group, while offering a traditional instruction to the control group. After offering the class, the study undertook a post-test, and verified the effect. In order to prove the test result, the study carried out a Hest using the SPSSWIN 12.0 statistical program, while the significance level being ${\alpha}$<.05. The conclusions obtained from this study include the following. All the six selected areas including 'problem-solving skills', 'communication skills', 'resource utilization competence', 'mathematical competence', 'interpersonal management competence' and 'self-management competence', which were supposed to be appropriate for this study among the sub-areas of Key competences, were found to show significant differences between the experimental group applied with a project method and the control group as a result of the post-test of the two groups. In summarizing the above research results, the class using a project method for the 'Making Model by Architecture' unit was discovered to be effective for improving Key competences. In particular, it may be more effective learning method for enhancing six areas greatly relevant to the project method among various sub-areas of Key competences.

• Progress in Medical Physics
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• v.15 no.2
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• pp.84-93
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• 2004

Stereotactic radiosurgery (SRS) is a technique that delivers a high dose to a target legion and a low dose to a critical organ through only one or a few irradiations. For this purpose, many mathematical methods for optimization have been proposed. There are some limitations to using these methods: the long calculation time and difficulty in finding a unique solution due to different tumor shapes. In this study, many clinical target shapes were examined to find a typical pattern of tumor shapes from which some possible ideal geometrical shapes, such as spheres, cylinders, cones or a combination, are assumed to approximate real tumor shapes. Using the arrangement of multiple isocenters, optimum variables, such as isocenter positions or collimator size, were determined. A database was formed from these results. The optimization procedure consisted of the following steps: Any shape of tumor was first assumed to an ideal model through a geometry comparison algorithm, then optimum variables for ideal geometry chosen from the predetermined database, followed by a final adjustment of the optimum parameters using the real tumor shape. Although the result of applying the database to other patients was not superior to the result of optimization in each case, it can be acceptable as a plan starling point.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.925-932
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• 2014

If a rotor possesses a high gyroscopic coupling or the running speed is high, the dynamical changes in the rotor become prominent. When active magnetic bearings are used to support such rotors, it is necessary for the bearing controller to take these dynamical changes into consideration. Independent-axis controllers, which are the most commonly used, modulate the bearing force solely based on the sensor output of the same axis. However, this type of controller has difficulties in overcoming the dynamical changes. On the other hand, mixed-axis controllers transform the sensor output into components corresponding to the vibrational modes. A separate controller can then be designed for each vibrational mode. In this way, the controller can be designed based on the dynamics of the rotor. In this paper, we describe a design process for a mixed-axis controller that uses a detailed mathematical model of the system. The performance of the controller is evaluated based on the ISO sensitivity requirements and unbalance response, while considering the change in the system dynamics due to the running speed.

• School Mathematics
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• v.12 no.2
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• pp.219-237
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• 2010

On inquiry of international comparison assessment, the Korean students achieve high scores in mathematics while they achieve relatively low scores in responses of the affective questionnaire. It can be an important point in mathematics education of Korea, but there are few studies which explore the specific reasons. So in this study, we analysed the results of PISA 2003(in math domain) based on multiple regression analysis and correlation analysis to investigate the reasons and features of those phenomena. We compared the results of Korean students with students of other countries. As a result, there were 7 factors which effect on Korean students' affective domain in mathematics learning and they were statistically significant. According to this study, it needs to improve students' positive attitudes to their school, mathematical interest, and positive self-concept. And it needs to develop an actual instrument to explore the affective domain which effect on mathematics learning.

• School Mathematics
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• v.15 no.4
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• pp.819-832
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• 2013

This study was performed to investigate the pedagogical knowledge of pre-service teachers and to explore the possibility of using Lesson Play in pre-service teacher education. Lesson Play refers to a lesson written in script form, featuring imagined interactions between a teacher and his/her students. The participants of this study were 20 pre-service teachers enrolled in mathematics education at a University in Seoul and they conducted a dialogue between a teacher and students who said that 91 is a prime number and 462 is a multiple number of 4. Conclusions were drawn based on the virtual scripts of pre-service teachers. First, it was found that the teaching strategies of pre-service teachers were not diverse. Second, pre-service teachers mainly explained the mathematical principles and concepts. Third, pre-service teachers could not understand the current state of students. Therefore, Lesson Play is helpful to analyse the pedagogical knowledge of pre-service teachers and is a applicable teaching method that can improve the practical knowledge of pre-service teachers.