• Journal of Educational Research in Mathematics
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• v.11 no.1
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• pp.193-206
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• 2001

This study was designed to develop investigation- and exploration- activities on Euclidean geometry with an exploratory type software, Geometer's Sketchpad, and to gain insights into the geometric reasoning abilities of college students working with the software. A package of Euclidean geometric activities with GSP was developed and four college students worked on the several activities with GSP and their geometric reasoning process were analyzed. Results indicated that GSP helped students solve problems in the several ways: to make conjectures and discover theorems by providing precise construction and measurement; to discover their proofs by providing the visual images and its manipulation; and to make students easily apply "what-if"strategies and expand and deepen their activities. Students' geometric reasoning was highly depended on analytic methods and their abilities with synthetic methods were shown very limited.

• Journal of Educational Research in Mathematics
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• v.10 no.1
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• pp.139-159
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• 2000

The experimental software such as Cabri II, The Geometer's Sketchpad, etc. provides dynamic environment which construct and explore geometric objects interactively and inductively. It has the effects on mathematics itself differently from other technologies that are used in instruction. What is its characteristics\ulcorner What are the educational implication of it for the learning of geometry\ulcorner How is mental reasoning of geometric problems changed by transformation of the means of representation and the environment to manipulate them\ulcorner In this study, we answer these questions through the review of the related literatures and the analysis of textbooks, teaching materials using it and curricular materials. Also, we identify implications about how the criteria for choosing geometic content and the ways of constructing context, for orchestrating the students' exploration with the secondary geometry curriculum, can be changed.

• School Mathematics
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• v.2 no.1
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• pp.111-144
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• 2000

The purpose of this study is to develop instruction sequence and teaching units for secondary school geometry using dynamic computer software like CabriII, GSP, Wingeom, Poly. For this purpose, literature was reviewed on various issues of geometry education and geometry curriculum using dynamic software. By the literature review, instructional sequence for teaching geometry in middle schools was designed. And, based on the newly developed instructional sequence, one sample teaching unit was developed. The basic principles for the development were to connect intuition geometry and formal geometry, and to emphasize students' investigative experience. Finally, experiment to check out teachers' response to the newly developed material was conducted by using questionnaire.

• Journal of Educational Research in Mathematics
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• v.9 no.2
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• pp.419-438
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• 1999

This paper explored the impact of dynamic geometry software such as CabriII, GSP on student's understanding deductive justification, on the assumption that proof in school mathematics should be used in the broader, psychological sense of justification rather than in the narrow sense of deductive, formal proof. The following results have been drawn: Dynamic geometry provided positive impact on interacting between empirical justification and deductive justification, especially on understanding the necessity of deductive justification. And teacher in the computer environment played crucial role in reducing on difficulties in connecting empirical justification to deductive justification. At the beginning of the research, however, it was not the case. However, once students got intocul-de-sac in empirical justification and understood the need of deductive justification, they tried to justify deductively. Compared with current paper-and-pencil environment that many students fail to learn the basic knowledge on proof, dynamic geometry software will give more positive ffect for learning. Dynamic geometry software may promote interaction between empirical justification and edeductive justification and give a feedback to students about results of their own actions. At present, there is some very helpful computer software. However the presence of good dynamic geometry software can not be the solution in itself. Since learning on proof is a function of various factors such as curriculum organization, evaluation method, the role of teacher and student. Most of all, the meaning of proof need to be reconceptualized in the future research.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.3
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• pp.701-722
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• 2010

Students have to investigate, experiment and inquire using the manipulative materials and real-world thing for studying Geometry. Manipulative materials activities encourage to understand mathematical concept and connection of symbol. Experiment activities using the computer focused the student's intuitive and inquisitive activities because of visualization of an abstract mathematics concept. This study developed a workbook through the use of manipulative materials and computer for operating and experimenting, and suggested a method for inquiry of geometrical properties and proved an effect. Manipulative materials-experiment activities was proven effective to middle level and lower level students in understanding the geometrical properties, and was proven effective to high level and lower level students when it comes to mathematical communication ability. When students operate, at first, they have to know about the feature and information of the materials, and the teacher has to make an elaborate plan and encourages the students to discuss about this.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.5
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• pp.507-513
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• 2008

In this paper, we present a development of an Avionics Hot Bench(AHB) used for the verification of operational flight programs and fault analysis using various simulation and stimulation software. We propose an application of the open system architecture to develop the AHB which can be used for the development of a real aircraft avionics system. In the design of the AHB, to reduce the development period and cost we use as many as commercial off-the-shelf hardware and software items. The developed AHB is compared with the existing proven AHB which was used for T-50 avionics system development. Thorough comparison between the test results using the developed AHB and those using the existing AHB is performed and the overall comparison results are very satisfactory.

• Clean Technology
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• v.27 no.2
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• pp.107-114
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• 2021

Material Life Cycle Assessment (MLCA) was performed to analyze the environmental impact characteristics of the Mg₂NiH_x-5 wt% CaO hydrogen storage composites' manufacturing process. The MLCA was carried out by Gabi software. It was based on Eco-Indicator 99' (EI99) and CML 2001 methodology. The Mg₂NiH_x-5 wt% CaO composites were synthesized by Hydrogen Induced Mechanical Alloying (HIMA). The metallurgical, thermochemical characteristics of the composites were analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), specific surface area analysis (Bruner-Emmett-Teller, BET), and thermogravimetric analysis (TGA). As a result of the CML 2001 methodology, the environmental impact was 78% for Global Warming Potential (GWP) and 22% for Eutrophication Potential (ETP). In addition, as a result of applying the EI 99' methodology, the acidification was the highest at 43%, and the ecotoxicity was 31%. Accordingly, the amount of electricity used in the manufacturing process may have an absolute effect on environmental pollution. Also, it is judged that the leading cause of Mg₂NiH_x-5 wt% CaO is the addition of CaO. Ultimately, it is necessary to research environmental factors by optimizing the process, shortening the manufacturing process time, and exploring eco-friendly alternative materials.