• School Mathematics
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• v.15 no.4
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• pp.889-920
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• 2013

The aim of this study is to look into the didactical background for introducing the concept of multiplication and teaching multiplication facts in elementary school mathematics and offer suggestions to improve teaching multiplication in the future. In order to attain these purposes, this study deduced and examined concepts of multiplication, situations involving multiplication, didactical models for multiplication and multiplication strategies based on key ideas with respect to the didactical background on teaching multiplication through a theoretical consideration regarding various studies on multiplication. Based on such examination, this study compared and analyzed textbooks used in the United States, Finland, the Netherlands, Germany and South Korea. In the light of such theoretical consideration and analytical results, this study provided implication for improving teaching multiplication in elementary schools in Korea as follows: diversifying equal groups situations, emphasizing multiplicative comparison situations, reconsidering Cartesian product situations for providing situations involving multiplication, balancing among the group model, array model and line model and transposing from material models to structured and formal ones in using didactical models for multiplication, emphasizing multiplication strategies and properties of multiplication and connecting learned facts and new facts with one another for teaching multiplication facts.

• Journal of KIISE:Software and Applications
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• v.28 no.12
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• pp.875-884
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• 2001

Although the self organizing map (SOM) is widely utilized in such fields of data visualization and topology preserving mapping, since it should have the topology fixed before trained, it has some shortcomings that it is difficult to apply it to practical problems, and classification capability is quite low despite better clustering performance. To overcome these points this paper proposes the dynamic topology preserving self-organizing map(DTSOM) that dynamically splits the output nodes on the map and trains them, and attempts to improve the classification capability by combining multiple DTSOMs K-Winner method has been applied to combine DTSOMs which produces K outputs with winner node selection method. This produces even better performance than the conventional combining methods such as majority voting weighting, BKS Bayesian, Borda, Condorect and reliability sum. DTSOM remedies the shortcoming of determining the topology in advance, and the classification rate increases significantly by combing multiple maps trained with different features. Experimental results with handwritten digit recognition indicate that the proposed method works out to problems of conventional SOM effectively so to improve the classification rate to 98.1%.

• School Mathematics
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• v.10 no.4
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• pp.557-571
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• 2008

The objective of this paper is to study De Morgan's thoughts on teaching and learning negative numbers. We studied De Morgan's point of view on negative numbers, and analyzed his didactical approaches for negative numbers. De Morgan make students explore impossible subtractions, investigate the rule of the impossible subtractions, and construct the signification of the impossible subtractions in succession. In De Morgan' approach, teaching and learning negative numbers are connected with that of linear equations, the signs of impossible subtractions are used, and the concept of negative numbers is developed gradually following the historic genesis of negative numbers. Also, we analyzed the strengths and weaknesses of the De Morgan's approaches compared with the mathematics curriculum.

• Journal of the Korean association of regional geographers
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• v.4 no.1
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• pp.27-41
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• 1998

The communication model has been accepted as the basic research paradigm of cartography since Board(1967) discussed the map/model analogy. In that paradigm, the function of maps was limited to the media of communication, and the functionality of maps was extremely emphasized. Therefore the model could not play its own role under the new environments such as computer, GIS, scientific visualization. Nowadays, the model has been attacked on several grounds and several alternatives have been suggested. Among the objections raised are (1) geographic visualization in which maps are considered as the tool of scientific visualization, (2) the contributions of art which are ignored in the positivist cartographic research, and (3) deconstructionist arguments which deny the scientific epistemology of map as an objective form of knowledge and recognize the textuality of maps including their metaphorical and rhetorical nature. Since a publication by McCormick et al, the scientific visualization based on the powerful computer graphics is used in a wide context. Maps are treated as the tools of scientific visualization and emphasis is on exploration of the geographic data to gain understanding and insight in the geographic visualization processes. The research on geographic visualization have stayed in the early stage of developing the conceptual model and the basic visualization tools. But, it is expected that the geographic or visual thinking which is emphasized in the geographic visualization will contribute the reestablishment of links between cartography and geography. Also, the development of scientific visualization tools and strategies will offer the opportunities to suggest a fresh idea, to synthesize information and develop holistic approaches to geographical problems.

• Journal of the Speleological Society of Korea
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• no.72
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• pp.65-74
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• 2006

• Journal of the Korean Society for information Management
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• v.24 no.3
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• pp.363-383
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• 2007

Global map of science, which is visualizing large scientific domains, can be used to visually analyze the structural relationships between major areas of science. This paper reviewed previous efforts on global science map, and then tried to making a science map of Korea with some new methods. There are several research groups on making global map of science including Dr. Small and Dr. Garfield of ISI (now Thompson Scientific), SCImago research group at the University of Granada, and Dr. Borner's InfoVis Lab at the Indiana University. They called their maps as science map or scientogram and called the activity of mapping science as scientography. Most of the previous works are based on citations between scientific articles. However citation database for Korean journal articles is still under construction. This research tried to make a Korean science map with the text in the proposals suggested for funding from Korean Research Foundation. Two kinds of method for generating networks of scientific fields are used. One is Pathfinder network (PFNet) alogorithm which has been used in several published bibliometric studies. The other is clustering-based network (CBnet) algorithm which was proposed recently as an alternative to PFNet. In order to take into account both views of the two algorithms, the resulting maps are combined to a final science map of Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.452-458
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• 2002

Although the reuse of the cached data for scrolling the map reduces the amount of passed data between client and server, it needs the conversions of data coordinates, selertive deletion of objects and cache compaction at client. The conversion is time intensive operation due to limited resources of mobile phones such as low computing power, small memory. Therefore, for the efficient map control in the vector map service based mobile phone, it is necessary to study the method for reducing wireless network bandwidth and for overwhelming the limited resources of mobile phone as well. This paper proposes the methods for racking pre-received spatial objects in client-server systems for mobile CIS. We also analyze the strengths and drawbacks between the reuse of cached data and transmission of raw data respectively.

• Journal of the Korean School Mathematics Society
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• v.12 no.3
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• pp.171-188
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• 2009

This study was designed for the purpose of identifying the influences of improved teaching method which constructed at the base of results of survey for finding present teaching-learning method of incenter and circumcenter of triangle. For this, we surveyed the students' understanding and math teachers' teaching method of incenter and circumcenter of triangle. Then, we designed alternative teaching method which innovated the problems from the resultic approaches of Incenter and circumcenter of triangle. And then, we taught students through new method and analyzed the influences of it to students.

• Journal of Elementary Mathematics Education in Korea
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• v.23 no.1
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• pp.1-17
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• 2019

In this study, prospective teachers were involved in arranging the teaching sequence of multiplication and division of fractions and decimal numbers based on their experience and knowledge of school mathematics. As a result, these activities provided an opportunity to demonstrate the prospective teachers' perception. Prospective teachers were able to learn the knowledge they needed by identifying the differences between their perceptions and curriculum. In other words, prospective teachers were able to understand the mathematical relationships inherent in the teaching sequence of multiplication and division of fractions and decimal numbers and the importance and difficulty of identifying students' prior knowledge and the effects of productive failures as teaching methods.

• Smart Media Journal
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• v.13 no.5
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• pp.26-32
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• 2024

This paper proposes a smart glass-based emergency tele-medical direction system. This system is designed for hospital specialists to provide remote medical guidance to on-site coast guards or emergency responders. To identify the requirements necessary for system development, relevant technological trends and case studies were analyzed. Based on this analysis, three system requirements were defined: 1) The system must be able to determine the necessity of patient transport, 2) It should assist in providing emergency medical care during transport to the hospital, and 3) It must be capable of transmitting patient information to medical facilities. A prototype that meets these requirements was developed and its usability was evaluated.