• International Journal of CAD/CAM
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• v.3 no.1_2
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• pp.67-75
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• 2003

Viewpoint-dependent feature-based modelling in computer-aided design is developed for the purposes of supporting engineering design representation and automation. The approach of this paper uses a combination of a multi-level modelling approach. This has two stages of mapping between models, and the multi-level model approach is implemented in three-level architecture. Top of this level is a feature-based description for each viewpoint, comprising a combination of form features and other features such as loads and constraints for analysis. The middle level is an executable representation of the feature model. The bottom of this multi-level modelling is a evaluation of a feature-based CAD model obtained by executable feature representations defined in the middle level. The mappings involved in the system comprise firstly, mapping between the top level feature representations associated with different viewpoints, for example for the geometric simplification and addition of boundary conditions associated with moving from a design model to an analysis model, and secondly mapping between the top level and the middle level representations in which the feature model is transformed into the executable representation. Because an executable representation is used as the intermediate layer, the low level evaluation can be active. The example will be implemented with an analysis model which is evaluated and for which results are output. This multi-level modelling approach will be investigated within the framework aimed for the design automation with a feature-based model.

• Wind and Structures
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• v.29 no.6
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• pp.389-403
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• 2019

In this study, two original spectral representations of stationary stochastic fields, say the continuous proper orthogonal decomposition (CPOD) and the frequency-wavenumber spectral representation (FWSR), are derived from the Fourier-Stieltjes integral at first. Meanwhile, the relations between the above two representations are discussed detailedly. However, the most widely used conventional Monte Carlo schemes associated with the two representations still leave two difficulties unsolved, say the high dimension of random variables and the incompleteness of probability with respect to the generated sample functions of the stochastic fields. In view of this, a dimension-reduction model involving merely one elementary random variable with the representative points set owing assigned probabilities is proposed, realizing the refined description of probability characteristics for the stochastic fields by generating just several hundred representative samples with assigned probabilities. In addition, for the purpose of overcoming the defects of simulation efficiency and accuracy in the FWSR, an improved scheme of non-uniform wavenumber intervals is suggested. Finally, the Fast Fourier Transform (FFT) algorithm is adopted to further enhance the simulation efficiency of the horizontal stochastic wind velocity fields. Numerical examplesfully reveal the validity and superiorityof the proposed methods.

• Bulletin of the Korean Mathematical Society
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• v.57 no.1
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• pp.207-218
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• 2020

Some modular representations of reflection groups related to Weyl groups are considered. The rational cohomology of the classifying space of a compact connected Lie group G with a maximal torus T is expressed as the ring of invariants, H*(BG; ℚ) ≅ H*(BT; ℚ)^W(G), which is a polynomial ring. If such Lie groups are locally isomorphic, the rational representations of their Weyl groups are equivalent. However, the integral representations need not be equivalent. Under the mod p reductions, we consider the structure of the rings, particularly for the Weyl group of symplectic groups Sp(n) and for the alternating groups A_n as the subgroup of W(SU(n)). We will ask if such rings of invariants are polynomial rings, and if each of them can be realized as the mod p cohomology of a space. For n = 3, 4, the rings under a conjugate of W(Sp(n)) are shown to be polynomial, and for n = 6, 8, they are non-polynomial. The structures of H*(BT^n-1; 𝔽_p)^A_n will be also discussed for n = 3, 4.

• Journal of the Korean Home Economics Association
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• v.51 no.1
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• pp.75-87
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• 2013

The purpose of this study was to explore the relationship between the preschoolers' hostile attributional bias and the narrative representation profiles. Forty five 4-year-old preschoolers (24 boys, 21 girls) participated in this study. In order to measure the children's narrative responses, MacArthur Story Stem Battery (MSSB) was used, and "a cartoon-based social perception task" was used to obtain preschoolers' hostile attributional bias. The data were analyzed using descriptive statistics and cluster analysis. The results were as follows. First, the rate of hostile attributional style of the subjects was 28.89%. Second, four profiles regarding the narrative representations of 4-year olds were found including: Prosocial (33.3%), Constrained (42.2%), Anxious/Restricted (6.7%), and Dysregulated (17.8%). Third, the rate of preschoolers' hostile attributional style differed by the preschoolers' narrative representation profile. Children with a Prosocial profile showed a less hostile attributional style than children with an Anxious/Restricted profile and Dysregulated profile. In conclusion, preschoolers' hostile attributional bias is related to the narrative representation profile.

• Asia pacific journal of information systems
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• v.29 no.1
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• pp.117-143
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• 2019

Advances in information technology (IT) bring about technological innovation in financial businesses, referred to as financial technology (fintech), beyond the traditional financial industry. While fintech implies more convenient and various financial services to customers, it leads to more complexity in the financial sector, as different industry players (e.g., IT firms) can participate in financial businesses. The complexity of fintech causes controversial issues related to policies and the appropriate development direction. In order to provide insight into the current state of fintech, this study explores the fundamental understanding of the fintech phenomenon from the perspective of the major stakeholders (i.e., financial authorities, financial companies, IT firms) in South Korea. This study analyzed news articles, where those stakeholders expressed their arguments, by using a content analysis. The study also conducted an intensive examination of their arguments by using a core-periphery approach of social representations. This study found that while the three beholders had a common opinion on deregulation of the fintech industry, each of them had different knowledge of the phenomenon. By revealing each beholder's structure of representations of fintech, this study not only provides common knowledge regarding fintech but also explicates the perceptual gaps among stakeholders. Findings of the study offer a big picture of current fintech initiatives, which can be useful knowledge for future research on fintech.

• Journal of Educational Research in Mathematics
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• v.27 no.3
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• pp.537-555
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• 2017

This paper compared and contrasted Korean and Singaporean textbooks in order to explore the direction and possibility of teaching the big ideas related to the addition and subtraction of fractions with different denominators proposed by Lee & Pang (2016a). Firstly, we examined the teaching sequences related to the addition of fractions with different denominators in a series of elementary mathematics textbooks of Korea and Singapore. We then analyzed what types of representations are used and how the representations are presented for the big ideas related to the addition of fractions with different denominators. The results of the analysis showed that the contents related to fraction addition are addressed more gradually and systematically in Singaporean textbooks compared to Korean counterparts. The graphical representations appeared in the Singaporean textbooks provide specific implications for teaching the big ideas of the addition of fractions with different denominators. Based on such implications, we expect that the big ideas related to the addition of fractions with different denominators will be addressed explicitly and systematically in Korean textbooks.

• Journal of Science Education
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• v.41 no.1
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• pp.152-165
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• 2017

The magnetic field due to a current is one of the core concepts in electromagnetism which has been taught in secondary science education. In addition, it is a representative example of using visual representations to explain the relation between invisible physical quantities; current and magnetic field. In this study we investigated middle school students' representational competence into three components; interpretation, construction, and application of visual representations. According to the analysis, more than 75 % of the respondents interpreted the meaning of the arrows for current and magnetic field correctly. However, half of them confused the movement of electric charges with the direction of magnetic field. Over 60 % of the students constructed the magnetic field representation as circular closed curves, but many of them could not express the density of field lines properly. In application of visual representations, more than half failed to draw the direction of compass needle correctly. The scores were in order of interpretation, construction and application. There were also significant correlations among three components of representational competence. More attention and research on students' representational competence and effective use of visual representations is needed to better support science learning and teaching.

• Education of Primary School Mathematics
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• v.21 no.4
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• pp.445-459
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• 2018

The purpose of this study is to provide a method to help elementary school students learn ratio-related concepts effectively through visual representations. This study was conducted to identify the differences in the composition of ratio-related concepts between Korean and Singaporean textbooks, reconstruct a unit of proportional expressions and distributions by using visual representations and confirm the differences in performance between an experimental and a comparison group of 6th grade students. While the experimental group mathematics lessons is from the reconstructed textbook, the comparison group lessons is from an existing textbook that does not include any reconstructive representations. A t-test of mean was applied to determine the differences between the experimental and comparison group. Analysis revealed significant differences in the mean between the experimental group and the comparison group, and the intermediate level group showed more improvement compared to the higher and lower level groups. An implication of this study is that the application of visual representations can assist students' understanding of ratio-related concepts.

• Honam Mathematical Journal
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• v.18 no.1
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• pp.33-42
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• 1996

• Honam Mathematical Journal
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• v.6 no.1
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• pp.59-83
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• 1984