• Journal of Elementary Mathematics Education in Korea
• /
• v.22 no.2
• /
• pp.199-220
• /
• 2018

This is a traditional education content that has been consistently handled in elementary school mathematics textbooks since the first curriculum in Korea. It has been mainly used to find out the properties of the solid figure or to save the surface area. However, as the importance of spatial ability is increasingly emphasized, the nets of solids can be a very suitable learning material for dealing with the spatial ability. Therefore, in this study, we examined how the nets of solids were taught in elementary school mathematics curriculum and textbooks in Korea, and based on the analysis, we analyzed the contents of the nets of solids covered in textbooks of Japan, Singapore, Finland and Hong Kong. Through this study, we suggested the enhancement of activities to find the right nets, the presentation of solid figure from various angles, and the nets of solids with patterns for improvement of spatial visualization and spatial orientation.

• The Journal of the Korea Contents Association
• /
• v.10 no.7
• /
• pp.63-69
• /
• 2010

This research does focus on supporting all of formal, or informal learning at real time. From industry or education field, learning training is according to worker's current situation or business context. And according to worker's current situation, or business flow, 3D immersion knowledge visualization is effective in the individual ability and the learning progress For this, workers listen to compound knowledge coaching advices at real time. Therefore we developed the realistic 3D based knowledge retrieval method to identify and retrieve multidimensional relation easily.

• Wind and Structures
• /
• v.26 no.4
• /
• pp.253-266
• /
• 2018

In this paper, the aerodynamic performance of two new cable surfaces with concave fillets (strakes) is examined and compared to plain, dimpled and helically filleted surfaces. To this end, an extensive wind-tunnel campaign was undertaken. Different samples with different concave fillet heights for both new surfaces were tested and compared to traditional surfaces in terms of aerodynamic forces (i.e. drag and lift reduction) and rain-rivulet suppression. Furthermore, flow visualization tests were performed to investigate the flow separation mechanism induced by the presence of the concave fillet and its relation to the aerodynamic forces. Both new cable surfaces outperformed the traditional surfaces in terms of rain-rivulet suppression thanks to the ability of the concave shape of the fillet to act as a ramp for the incoming rain-rivulet. Furthermore, both new surfaces with the lowest tested fillet height were found to have drag coefficients in the supercritical Reynolds range that compare favorably to existing cable surfaces, with an early suppression of vortex shedding.

• 한국가시화정보학회:학술대회논문집
• /
• 2004.11a
• /
• pp.48-51
• /
• 2004

Chemical Mechanical Polishing(CMP) is popularly used in production of semiconductor because of large area polishing ability probability of improvement for more integrated circuit. However, present CMP processing causes some non-uniformity errors which can be critical for highly integrated circuit. Previous studies predict that flow-field of slurry during CMP can create non-uniformity, but no quantitative measurement has conducted. In this study, using PIV, slurry velocity flow-field during CMP is measured by changing the ratio of RPM of pad and carrier with tuned PIV system adequate for small room in CMP machine and Cabot's non-groove pad Epad-A100. The result show that velocity of slurry is majorly determined by pad-rpm and the ratio of between carrier and pad rpm make some changes in streamlines.

• Journal of the Korean Society of Visualization
• /
• v.7 no.1
• /
• pp.14-20
• /
• 2009

In comparison with previous researches fur swirling flow, the spiral flow self-generated in the spiral flow nozzle has some different characteristics. It is not needed a compulsive tangential momentum to get its velocity component and has long potential core, relatively low swirl ratio, and high focusing ability. In this study, the self-generated mechanism of the spiral flow was clarified and the effect on the width of annular slit on spiral flow characteristics was investigated experimentally and numerically. As a result, the existence of tangential velocity component regardless of a compulsive angular momentum is clarified and the results obtained by experiment have a satisfactory agreement with those by numerical method, quantitatively and qualitatively.

• The Mathematical Education
• /
• v.45 no.3 s.114
• /
• pp.263-273
• /
• 2006

The purpose of this paper is to research the factors and the effects of immediacy in mathematics teaching and learning and mathematical problem solving. The factors of immediacy are visualization, functional fixedness and representatives. In special, students can apprehend immediately the clues and solution using the visual representation because of its properties of finiteness and concreteness. But the errors sometimes originate from visual representation which come from limitation of the visual representation. It suggests that students have to know conceptual meaning of the visual representation when they use the visual representation. And this phenomenon is the same in functional fixedness and representatives which are the factors of immediacy The methods which overcome the errors of immediacy is that problem solvers notice the limitation of the factors of immediacy and develop the meta-cognitive ability. And it means we have to emphasize the logic and the intuition in mathematical teaching and learning. Clearly, we can't solve all mathematical problems using only either the logic or the intuition.

• Journal of Korean Institute of Industrial Engineers
• /
• v.37 no.4
• /
• pp.400-407
• /
• 2011

Modeling and analysis of high-dimensional spectral data provide an opportunity to uncover inherent patterns in various information-rich data. Orthogonal signal correction (OSC) a preprocessing technique has been widely used to remove unwanted variations of spectral data that do not contribute to prediction or classification. In the present study we propose a novel OSC algorithm called adjusted direct OSC to improve visualization and the ability of classification. Experimental results with real mass spectral data from condom lubricants demonstrate the effectiveness of the proposed approach.

• Korean Journal of Child Studies
• /
• v.18 no.2
• /
• pp.105-120
• /
• 1997

The purpose of this study was to investigate children's abilities of self-control and visual information processing based on their experience with video games. Participants, divided by prior exposure to video games, were 44 seven-year-old and 48 eleven-year-old boys. The impulsive tendency of children was measured through the MFFT and The delayed satisfaction test. Visual information processing ability was assessed through perceptual speed, mental rotation, and spatial visualization tasks. No differences were found between more-and less-video-game-experienced boys. Significant differences, however, were found in visual information processing abilities. More experienced boys performed better in mental rotation and spatial visualization tasks than less experienced boys.

• Journal of the Korean Society of Visualization
• /
• v.20 no.3
• /
• pp.42-48
• /
• 2022

The shortage of available freshwater is a major global issue worldwide and an increasing demand for clean water requires efficient water purification strategies. Here we describe a method to drastically increase the efficiency of a microreactor for photocatalytic water purification. To find out how the shape of the catalyst affects water purification, nanostructured catalysts of different structures, such as dense film, nanorod, and nanohelix, are prepared and their water purification characteristics are analyzed. Compared to the flat catalyst, the nanostructured catalyst showed a distinct ability in its pollutant degradation, but the detailed structural variation does not significantly affect the water purification. To further increase efficiency, we apply a micromixer to nanorod-based microreactor, which allows even enhanced mass transfer. This enables the solution of the water purification problem and greatly contributes to the industries where the efficiency of photocatalytic activity has attracted extensive interest.

• Journal of Gifted/Talented Education
• /
• v.8 no.2
• /
• pp.69-89
• /
• 1998

The purpose of this study is to develop a test which can be used in identification of the gifted students in the area of mathematics. This study was carried out for two years from 1996. Mathematical giftedness is, in this study, regarded as a result of interaction of mathematical thinking ability, mathematical creativity, mathematical task committment, background knowledge. This study presumed that mathematical thinking ability is composed of seven thinking abilities: intuitive insights, ability for information organization, ability for visualization, ability for mathematical abstraction, inferential thinking ability(both inductive and deductive thinking abilities), generalization and application ability, and reflective thinking. This study also presupposed that mathematical creativity is composed of 3 characteristics: fluency, flexibility, originality. The test for mathematical creative problem solving ability was developed for primary, middle, and high school students. The test is composed of two parts: the first part is concentrated more on divergent thinking, while the second part is more on convergent thinking. The major targets of the test were the students whose achievement level in mathematics belong to top 15~20% in each school. The goodness of the test was examined in the aspects of reliability, validity, difficulty, and discrimination power. Cronbach $\alpha$ was in the range of .60~.75, suggesting that the test is fairly reliable. The validity of the test was examined through the correlation among the test results for mathematical creative problem solving ability, I. Q., and academic achievement scores in mathematics and through the correlation between the scores in the first part and the scores in the second part of the test for mathematical creative problem solving ability. The test was found to be very difficult for the subjects. However, the discrimination power of the test was at the acceptable level.