• East Asian mathematical journal
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• v.34 no.2
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• pp.203-217
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• 2018

This study examined preservice elementary teachers' patterns and tendencies in thinking of drawn models of multiplication with fractions. In particular, it investigated preservice elementary teachers' work in a context where they were asked to select among drawn models for symbolic expressions illustrating multiplication with non-whole number fractions including a mixed number. Preservice teachers' interpretations of fraction multiplication used in interpreting different types of drawn models were analysed-both quantitatively and qualitatively. Findings and implications are discussed and further research is suggested.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.384-384
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• 2000

In adaptive neuro-control, neural networks are used to approximate the unknown plant nonlinearities. Until now, most of the papers in the field of controller design fur nonlinear system using neural networks considers the affine system with fixed number of neurons. This paper considers nonaffne nonlinear systems and dynamic variation of the number of neurons. Control laws and adaptive laws for weights are established so that the whole system is stable in the sense of Lyapunov.

• Communications for Statistical Applications and Methods
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• v.11 no.3
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• pp.465-474
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• 2004

Data visualization is the automation process and the discovery process to data sets in an effort to discover underlying information from the data. It provides rich visual depictions of the data. It has distinct advantages over traditional data analysis techniques such as exploring the structure of large scale data set both in the sense of number of observations and the number of variables by allowing great interaction with the data and end-user. We discuss the principles of data visualization and evaluate the characteristics of various tools of visualization according to these principles.

• School Mathematics
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• v.9 no.3
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• pp.353-373
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• 2007

The purpose of this study was to provide instructional suggestions by investigating the spatial sense and spatial reasoning ability of 6th grade students. The questionnaire consisted of 20 questions, 10 for spatial visualization and 10 for spatial orientation. The number of subjects for the survey was 145. The processes through which the students solved the problems were the basis for the assessment of their spatial reasoning. The result of the survey is as follows: First, students performed better in spatial visualization than in spatial orientation. With regard to spatial visualization, they were better in transformation than in rotation. With regard to spatial orientation, students performed better in orientation sense and structure cognitive ability than in situational sense. Second, the students that weren't excellent in spatial visualization tended to answer the familiar figures without using mental images. The students who lacked spatial orientation experienced difficulties finding figures observed from the sides. Third, students had high frequency rate on the cognition and use of transformation, the development and application of visualization methods and the use of analysis and synthesis. However they had a lower rate on a systematic approach and deductive reasoning. Further detailed investigation into how students use spatial reasoning, and apply it to actual teaching practice as a device for advancing their geometric thinking is necessary.

• Korean Security Journal
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• no.16
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• pp.305-319
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• 2008

There are always possibilities for conflicts among individuals, between individuals and groups, and among groups because of the complex and diverse nature of contemporary society. Some form of bodyguard is required to protect oneself from this constant possibility of conflicts and thus the concept of security was developed to meet the needs of one's safety. Furthermore, the increase in the number of crime and intellectual crimes now threatens not only the people with power, fortune, reputation but also all citizens. Meeting the need for safety became a challenging task for the world and a security-related industry as well as security-related careers were born. Therefore, schools and security institutions must provide education and training to nurture morality and stable psychological condition for their students/trainees. In order to offer them such working and educational environments, utilizing the sixth-sense the five senses is recommended and it is called security psychology training. This study identifies the psychology, the five senses, and the sixth sense of bodyguards while on duty and explores the training and education contents to utilize the sixth sense.

• Journal of the Korean Applied Science and Technology
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• v.40 no.3
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• pp.374-384
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• 2023

Universities that previously targeted in 20s have recently diversified their operation methods, founding purposes, and target. With a significant decrease in the school-age population relative to the number of universities, universities are making their best efforts to secure new students and minimize student attrition. In this study, an online survey was conducted to empirically examine the effects of motivation for major selection and sense of belonging on learning persistence intention among students in beauty-related departments at 2-year and 4-year general universities and cyber universities. The collected data from 119 students at general universities and 113 students at cyber universities were analyzed using SPSS 28. The key findings can be summarized as follows: For general universities, motivation for major selection did not have a significant effect on learning persistence intention, but sense of belonging had a significant positive effect. Additionally, an interaction effect was observed, indicating that as the sense of belonging increased, extrinsic motivation significantly increased learning persistence intention. For cyber universities, intrinsic motivation and sense of belonging among motivations for major selection had a significant positive effect on learning persistence intention, while the moderating effect of sense of belonging in the relationship between motivation for major selection and learning persistence intention was not significant. In summary, for general universities, the factor that influenced students' learning persistence intention was a sense of belonging to the university, while for cyber universities, intrinsic motivation played a significant role. These findings are expected to provide meaningful insights and data for universities to develop effective policies for preventing student attrition.

• Journal of the Korean Mathematical Society
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• v.47 no.4
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• pp.861-877
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• 2010

The works of Erd$\ddot{o}$s et al. about expansions of 1 with respect to a non-integer base q, referred to as q-expansions, are investigated to determine how far they continue to hold when the number 1 is replaced by a positive number x. It is found that most results about q-expansions for real numbers greater than or equal to 1 are in somewhat opposite direction to those for real numbers less than or equal to 1. The situation when a real number has a unique q-expansion, and when it has exactly two q-expansions are studied. The smallest base number q yielding a unique q-expansion is determined and a particular sequence is shown, in certain sense, to be the smallest sequence whose corresponding base number q yields exactly two q-expansions.

• KIISE Transactions on Computing Practices
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• v.23 no.4
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• pp.226-231
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• 2017

Word representation, an important area in natural language processing(NLP) used machine learning, is a method that represents a word not by text but by distinguishable symbol. Existing word embedding employed a large number of corpora to ensure that words are positioned nearby within text. However corpus-based word embedding needs several corpora because of the frequency of word occurrence and increased number of words. In this paper word embedding is done using dictionary definitions and semantic relationship information(hypernyms and antonyms). Words are trained using the feature mirror model(FMM), a modified Skip-Gram(Word2Vec). Sense similar words have similar vector. Furthermore, it was possible to distinguish vectors of antonym words.

• Journal of Industrial Convergence
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• v.21 no.5
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• pp.97-107
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• 2023

The purpose of this study was to provide basic data to improve happiness by verifying the mediating effect of career decision in the relationship between civic consciousness, community consciousness, career decision, and happiness of middle school students. As for the analysis data, the "2020 Gen Z Teenage Values Survey" data surveyed by the Korea Youth Policy Institute was used. Among the survey subjects, 2,703 middle school students who met the purpose of this study were sampled and analyzed using the SPSS WIN 25.0 program. For the analysis method, frequency analysis, descriptive statistical analysis, correlation analysis, and PROCESS MACRO Model Number 4 were used to verify the mediating effect, and indirect effects and significance were analyzed by applying the Bootstrap technique. The results of the study showed, first, that middle school students' sense of citizenship and community had a positive effect on happiness. Second, in the relationship between civic consciousness and happiness, career decision had a partial mediating effect. Third, in the relationship between community consciousness and happiness, career decision had a partial mediating effect. In other words, it is meaningful in that it presented policy alternatives and practical programs to improve the happiness of middle school students.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1031-1046
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• 2018

Vehicular ad hoc network (VANET) is a dedicated network to connect vehicles without any centralized administration or infrastructure. The wireless access in vehicular environments (WAVE) protocol leveraging IEEE 1609/802.11p is widely implemented for VANETs. However, in congested traffic situation, the performance of the WAVE system degrades significantly due to serious collision, especially for safety related broadcast services on the control channel (CCH) interval due to the inherent drawback of its collision avoidance mechanisms called carrier sense multiple access with collision avoidance (CSMA/CA). In this paper, we propose a method that can decrease the number of frame collisions in CCH with a few modifications to the IEEE 802.11p protocol. In the paper, vehicles still employ CSMA/CA to compete for the channel access opportunity. However, by taking advantage of periodicity of synchronization interval, a two-state switching scheme introducing two new inter frame space (IFS) is proposed to reduce the number of competing vehicles substantially and as a result, the collision probability is significantly decreased. The simulation results demonstrate the superiority of the proposed method in packet collision rate.