• 제목/요약/키워드: Rational

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RATIONAL HOMOLOGY DISK SMOOTHINGS AND LEFSCHETZ FIBRATIONS

  • Hakho Choi
    • 대한수학회지
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    • 제60권1호
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    • pp.227-253
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    • 2023
  • In this article, we generalize the results discussed in [6] by introducing a genus to generic fibers of Lefschetz fibrations. That is, we give families of relations in the mapping class groups of genus-1 surfaces with boundaries that represent rational homology disk smoothings of weighted homogeneous surface singularities whose resolution graphs are 3-legged with a bad central vertex.

유리수 개념에 대한 대학생들의 이해와 추론 (University Students' Understanding and Reasoning about Rational Number Concept)

  • 강윤수
    • 한국학교수학회논문집
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    • 제13권3호
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    • pp.483-498
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    • 2010
  • 이 연구의 목적은, 유리수 개념에 대한 대학생들의 이해와 추론 성향을 알아보는 것이다. 이를 위해, 우리나라 사법대학생 (33), 공과대학생 (35), 미국대학생 (28) 등으로 구성된 세 그룹을 대상으로 설문조사를 실시하였다. 설문지는 유리수 개념 이해 관련 네 문제와 연산 추론 성향 관련 세 문제로 구성되었다. 네 문제에 대해서는 복수응답을 요구하고 연산 관련 세 문제는 선호하는 순서를 표시하도록 하였다. 그 결과, 설문 조사에 참여한 대학생들이 유리수 개념의 여러 측면을 정확하게 이해하지 못하며, 유리수 연산에 대해서 개념적 방법보다는 메커니즘적 접근방식을 선호하는 것을 확인하였다. 뿐만 아니라, 분수, 비, 비례, 유리수 등과 관련된 문맥에서 비논리적인 추론을 하고 이들 사이의 연계성을 정확하게 인식하지 못해 개념적으로 혼란스러워하는 것을 확인하였다.

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죄수딜렘마(PD) 게임상황을 활용한 환경교육의 가능성 (An Alternative Approach for Environmental Education to overcome free rider egoism based on the Perspectives of Prisoner's Dilemma Situation)

  • 김태경
    • 한국환경교육학회지:환경교육
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    • 제13권2호
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    • pp.38-50
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    • 2000
  • We are evidently Home Economicus, egoistic rational utility maximiger, and all the capitalism economic situation make us adapt to such life, and recognize that it is rational to act like that. This can be demonstrated in Prisoner′s Dilemma(PD) which always select the non-cooperative choice for free rider in rational selection process of public goods. This paper notice the "what is problem\ulcorner"The problem is not in free rider itself but in free rider egoism. The practical behavior of free rider egoism can be explained by way of Prisoner′s Dilemma. In PD situation, the prisoner makes a rational choice, non-cooperative alternative, but he doesn′arrive at preto-optimality. It is dilemma. Why can′t he arrive \ulcorner Because he is isolated from other prisoner. So we call it prisoner′s dilemma. The PD situation can be compared with our real economic life, which, we think, have kept by rational choice of the public goods. We actually have made our life as an individual one although we organized communities of capitalism. Of course, we know each others as members of same society, but each individual being can′t secure the belief, which has composed basis of community. So, it is very similar and common between PD situation and our real economic life in the production of public goods. We conclude that this non-cooperative process of PD situation can be utilized as instrument of EE. So this non-cooperative process can show us the effectiveness of EE as follows. \circled1 Game situation life PD can be used as good instrument for explaining the rational selection dilemma(error) to Homo-Economicus, the rational agent, with the optimal and rational language. \circled2 We can show that the selection result is dilemma, not arrive pareto - optimality. \circled3 The dilemma can be resolved with accomplishing the good communal life based on the belief, not on the isolation.

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PERIODICITY AND ATTRACTIVITY FOR A RATIONAL RECURSIVE SEQUENCE

  • ZHANG LIJIE;ZHANG GUANG;LIU HUI
    • Journal of applied mathematics & informatics
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    • 제19권1_2호
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    • pp.191-201
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    • 2005
  • In this paper, the existence of periodic positive solution and the attractivity are investigated for the rational recursive sequence $x_{n+1} = (A + ax_{n_k})/(b + x{n-l})$, where A, a and b are real numbers, k and l are nonnegative integer numbers.