• 제목/요약/키워드: mathematical analysis

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박판성형 해석용 마찰 모델(2부:수학적 모델) (Friction Model for Sheet Metal Forming Analysis(Part 2 :Mathematical Model))

  • 금영탁;이봉현
    • 소성∙가공
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    • 제13권5호
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    • pp.461-465
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    • 2004
  • Based on the experimental observation, the mathematical friction model, which is an essential information for analyzing the forming process of sheet metal, is developed considering lubricant viscosity, surface roughness and hardness, punch comer radius, and punch speed. By comparing the punch load found by FEM with a proposed friction model with experimental measurement when the coated and uncoated steel sheets are formed in 2-D geometry in dry and lubricant conditions, the validity and accuracy of the developed friction model are demonstrated.

PRACTICAL FHE PARAMETERS AGAINST LATTICE ATTACKS

  • Cheon, Jung Hee;Son, Yongha;Yhee, Donggeon
    • 대한수학회지
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    • 제59권1호
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    • pp.35-51
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    • 2022
  • We give secure parameter suggestions to use sparse secret vectors in LWE based encryption schemes. This should replace existing security parameters, because homomorphic encryption (HE) schemes use quite different variables from the existing parameters. In particular, HE schemes using sparse secrets should be supported by experimental analysis, here we summarize existing attacks to be considered and security levels for each attacks. Based on the analysis and experiments, we compute optimal scaling factors for CKKS.

수리논술형 문제에 대한 초등학교 5학년 학생들의 문제해결력과 수학적 정당화 과정 분석 (An Analysis of Problem-solving Ability and Mathematical Justification of Mathematical Essay Problems of 5th Grade Students in Elementary School)

  • 김영숙;방정숙
    • 한국수학교육학회지시리즈A:수학교육
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    • 제48권2호
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    • pp.149-167
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    • 2009
  • This study was aimed to examine problem-solving ability of fifth graders on two types of mathematical essay problems, and to analyze the process of mathematical justification in solving the essay problems. For this purpose, a total of 14 mathematical essay problems were developed, in which half of the items were single tasks and the other half were data-provided tasks. Sixteen students with higher academic achievements in mathematics and the Korean language were chosen, and were given to solve the mathematical essay problems individually. They then were asked to justify their solution methods in groups of 4 and to reach a consensus through negotiation among group members. Students were good at understanding the given single tasks but they often revealed lack of logical thinking and representation. They also tended to use everyday language rather than mathematical language in explaining their solution processes. Some students experienced difficulty in understanding the meaning of data in the essay problems. With regard to mathematical justification, students employed more internal justification by experience or mathematical logic than external justification by authority. Given this, this paper includes implications for teachers on how they need to teach mathematics in order to foster students' logical thinking and communication.

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