• Journal of Radiation Protection and Research
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• v.33 no.1
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• pp.21-26
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• 2008

When the calibration on Liquid Scintillation Counter using the Solid $^3H$ Standard Source of 200,000DPM is executed, the uncertainty due to activity and geometry difference, exists. Therefore, this paper intends to evaluate environmental samples comparatively accurately as decreasing this uncertainty existing in the process of calibration. For this, measurements on samples manufactured by $^3H$ Standard Source and sensitivity study were performed. Also, this paper verified calibration results using Radioactivity-Error-Analysis Method, and evaluated quantitatively the effect by geometry and activity difference based on verification result. According to the result of sensitivity study, in case of using the exposure time of 75 sec and Repeat method, the measuring accuracy and precision of about $1{\sim}3%$ were increased in comparison with the existing method. By analysis result, the effect by activity difference did not appear, and a plastic cell existing into Teflon vial made a role as reflector. The less the effect of plastic cells are decreased, the more activity is high, and the effect of those can be neglected at the activity of 200,000 DPM.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.5
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• pp.471-478
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• 2016

This paper proposes the results of analysis of correlation between satellite geometry elements for an effective use of satellite images. To achieve accurate positional information, stereo images have normal range of convergence and BIE (BIsector Elevation) angles which are greatly influenced by azimuth and elevation angle of individual image. In this paper, the variations of convergence and BIE angles are estimated according to azimuth angle differences between two images and each elevation angle. The analysis provided strong support for predicting stereo geometry without complex analysis of epiploar geometry or mathematics. The experiment results showed that more than 150°, 130°, and 100° azimuth angle differences need to be constructed when elevation angle of two images is 50°, 60°, and 70°, respectively, in order to make the convergence and BIE angle within normal range. The results are expected to be fully used for various application using stereo images.

• Journal for History of Mathematics
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• v.19 no.2
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• pp.101-114
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• 2006

The content and method of geometry taught in secondary school is rooted in 'Elements' by Euclid. On the other hand, however, there are differences between the content and structure of the current textbook and the 'Elements'. The gaps are resulted from attempts to develop the geometry education. Specially, the content and method for the proportional relations of geometric figures has been varied. In this study, we reviewed the changes of the proportional relations of geometric figures with pedagogical point of view. The conclusion that we came to is that the proportional relations in incommensurable case Is omitted in secondary school. Teacher's understanding about the proportional relations of geometric figures is needed for meaningful geometry education.

• Journal for History of Mathematics
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• v.18 no.4
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• pp.29-38
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• 2005

This Paper discusses the history of the conflicts between synthesis and analysis, from those in heuristic and logic development style in ancient Greek to those in projective geometric methods. The two methods, which originally displayed difference in heuristic, offer the base for the two fields of geometry, the analytic geometry and the synthetic geometry in the 18th century as they originated from the field of geometry. As to the 19th century, they even display antagonistic aspects derived by having other perspectives about the true nature of mathematic but finally lose the reason of conflict as the ancient times when the dialectical sublation of both had been proposed.

• School Mathematics
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• v.15 no.2
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• pp.481-501
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• 2013

The purpose of this study is to review the role of dragging in dynamic geometry environments. Dragging is a kind of dynamic representations that dynamically change geometric figures and enable to search invariances of figures and relationships among them. In this study dragging in dynamic geometry environments is divided by three perspectives: dynamic representations, instrumented actions, and affordance. Following this review, six conclusions are suggested for future research and for teaching and learning geometry in school geometry as well: students' epistemological change of basic geometry concepts by dragging, the possibilities to converting paper-and-pencil geometry into experimental mathematics, the role of dragging between conjecturing and proving, geometry learning process according to the instrumental genesis perspective, patterns of communication or discourse generated by dragging, and the role of measuring function as an affordance of DGS.

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.379-385
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• 1994

The sensitivity vector which depends on geometry of object illumination angles and distances of ESPI was analyzed. And the sensitivities of in-plane and out-of-plane displacements have been investigated. From these results, we have the conclusion that it is useful to use the diverging beam for object illumination. With diverging object illumination, only little errors are occurred when we approximate the sensitivity vector to constant all over the object surface.urface.

• Journal of the Korean School Mathematics Society
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• v.16 no.1
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• pp.187-200
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• 2013

This study, as part of the research on mathematics teacher knowledge analyzed the differences in understanding and familiarity on geometric knowledge of middle-high school teachers. Through this study, survey was carried out using a questionnaire and examination for 80 middle-high school teachers. As the result, differences between familiarities about believing in knowing about the proposition, and actually understanding why the proposition is established, was big. These results can provide us implications on the education of teachers and pre-service teachers of middle-high school.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.2
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• pp.401-420
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• 2010

The purpose of this research is to find out effectiveness of geometry learning through spatial reasoning activities on mathematical problem solving ability and mathematical attitude. In order to proof this research problem, the controlled experiment was done on two groups of 6th graders in N elementary school; one group went through the geometry learning style through spatial reasoning activities, and the other group went through the general geometry learning style. As a result, the experimental group and the comparing group on mathematical problem solving ability have statistically meaningful difference. However, the experimental group and the comparing group have not statistically meaningful difference on mathematical attitude. But the mathematical attitude in the experimental group has improved clearly after all the process of experiment. With these results we came up with this conclusion. First, the geometry learning through spatial reasoning activities enhances the ability of analyzing, spatial sensibility and logical ability, which is effective in increasing the mathematical problem solving ability. Second, the geometry learning through spatial reasoning activities enhances confidence in problem solving and an interest in mathematics, which has a positive influence on the mathematical attitude.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.335-344
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• 2012

Osteoporosis is increasing in Korea as it becomes an aging society with the rapid economic growth and the development of medical technology. Osteoporosis also develops due to chemo and radiation therapy of cancer which also increases owing to Westernized diet. Osteoporosis is caused by reduced bone density, has close relationship with the change of geometry of proximal femur, which is a factor of hip fracture risk. The purpose of this study was the analysis of the correlations of osteoporosis and the change of geometry of proximal femur, which was observed according to T-score variance. The 350 male and female patients are chosen from D hospital in Busan, who were classified by age, sex and T-score values (normal, osteopenia, and osteo porosis). The results show that the age and gender have significant difference in the incidence of osteoporosis; the disease classification according to T-score value has significant difference in the geometry of the proximal femur such as Cortical ratio calcar, Cortical ratio shaft, Hip/shaft Angle, Strength index, Section modulus, CSMI, and CSA, and is highly correlated with the incidence of osteoporosis. Therefore, the findings of this research is that the change of the geometry of the proximal femur could be used as an indicator in the diagnosis of osteoporosis, could enhance the accuracy of the diagnosis in the future, and could be used as a clinical predictive factors through the analysis of the correlations of T-score variance and the geometry changes of the proximal femur.

• School Mathematics
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• v.9 no.4
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• pp.523-533
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• 2007

This article focused the meaning of Pythagoras' and Euclid's proof about the Pythagorean theorem in a historical and mathematical perspective. Pythagoras' proof using similarity is based on the arithmetic assumption about commensurability. However, Euclid proved the Pythagorean theorem again only using the concept of dissection-rearrangement that is purely geometric so that it does not need commensurability. Pythagoras' and Euclid's different approaches to geometry have to do with Birkhoff's axiom system and Hilbert's axiom system in the school geometry Birkhoff proposed the new axioms for plane geometry accepting real number that is strictly defined. Thus Birkhoff's metrical approach can be defined as a Pythagorean approach that developed geometry based on number. On the other hand, Hilbert succeeded Euclid who had pursued pure geometry that did not depend on number. The difference between the proof using similarity and dissection-rearrangement is related to the unsolved problem in the geometry curriculum that is conflict of Euclid's conventional synthetical approach and modern mathematical approach to geometry.