• East Asian mathematical journal
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• 제32권3호
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• pp.377-385
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• 2016

Global attractor is a basic concept to study the long-time behavior of solutions of the various equations. This paper is investigated with the existence of a global attractor for the beam equation $$u_{tt}+{\Delta}^2u-{\nabla}{\cdot}\{{\sigma}({\mid}{\nabla}u{\mid}^2){\nabla}u\}+f(u)+a(x)g(u_t)=h,$$ using multipliers technique and Nakao's Lemma.

• 호남수학학술지
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• 제26권3호
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• pp.309-330
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• 2004

In this paper, we apply the concept of intuitionistic fuzzy sets to theory of semigroups. We give some properties of intuitionistic fuzzy ideals and intuitionistic fuzzy bi-ideals, and characterize which is left [right] simple, left [right] duo and a semilattice of left [right] simple semigroups or another type of semigroups in terms of intuitionistic fuzzy ideals and intuitionistic fuzzy bi-ideals.

• 한국수학교육학회지시리즈A:수학교육
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• 제20권3호
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• pp.23-26
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• 1982

Many interesting properties of a space curve C in E$^3$ may be investigated by means of the concept of spherical indicatrix of tangent, principal normal, or binormal, to C. The purpose of the present paper is to derive the representations of the Frenet frame field., curvature, and torsion of spherical indicatrix to C in terms of the quantities associated with C. Furthermore, several interesting properties of spherical indicatrix are found in the present paper.

• 대한수학회보
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• 제59권1호
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• pp.179-190
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• 2022

A cascade of toric log del Pezzo surfaces of Picard number one was introduced as a language of classifying all such surfaces. In this paper, we introduce a generalized concept, a semicascade of toric log del Pezzo surfaces. As applications, we discuss Kähler-Einstein toric log del Pezzo surfaces and derive a bound on the Picard number in terms of the number of singular points, generalizing some results of Dais and Suyama.

• 한국수학사학회지
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• 제16권3호
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• pp.57-68
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• 2003

Infinity is very important concept in mathematics. In history of mathematics, potential infinity concept conflicts with actual infinity concept for a long time. It is reason that actual infinity concept causes difficulty in our perceptions. This phenomenon is called epistemological obstacle by Brousseau. So, in this paper, we examine the infinity in terms of mathematical didactics. First, we examine the history of development of infinity and reveal the similarity between the history of debate about infinity and episternological obstacle of students. Next, we investigate obstacle of students about infinity and the contents of curriculum which treat the infinity Finally, we suggest the methods for overcoming obstacle in learning of infinity concept.

• 터널과지하공간
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• 제28권1호
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• pp.25-37
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• 2018

미고결 암석에 대한 Creep 특성을 분석하고자 Burger 모델을 이용하였다. Burger 모델은 자료쌍 D(u,t)으로부터 4개의 역학적 매개변수를 결정 하여야 한다. 본 연구에서는 수학적 개념 해를 적용하여 매개변수를 결정 하였다. 미고결 암석에 대한 Burger 모델의 결정된 매개변수를 이용하여 Creep을 3년간 가속시켰다. 그 결과 Creep 거동은 수렴이 되지 않고 지속적인 변형거동을 보였다. 따라서 본 광산에서는 Roofbolt 보다 U-Beam 적용이 안정성 측면에서 더 적합 할 것으로 분석 되었다.

• East Asian mathematical journal
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• 제33권4호
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• pp.431-451
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• 2017

This is a descriptive study with the intent of providing a rich characterization of teachers' perceptions of rate of change. The nature of teachers' perceptions and differences among teachers were examined by collecting data through a survey on teachers' conceptions of rate of change in terms of learning goals, prerequisites, and beliefs about teaching and learning of rate of change, and an interview individually assessing teachers' concept images and definitions. The participating 13 teachers were selected to provide a range of similar and contrasting levels of experiences based on the teachers' educational background and the number of years they had been teaching. Findings and implications of this study are discussed.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제34권3호
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• pp.355-372
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• 2020

무한급수 개념은 학부의 전공 수학 교육과정의 중요한 주제이다. 여러 세기 동안 그것은 학습자에게 직관에 반대되는 장애를 제공했을 뿐만 아니라 해석학 연구의 중심적 역할을 해 왔다. 수학의 역사에서 무한급수 개념에 대한 이해가 미적분학 발달의 기초가 되었듯이 현재의 학생들에게 무한급수 개념에 대한 이해는 전공 수학을 학습하는 데 꼭 필요하다. 무한합의 개념을 가진 학생 대부분은 무한급수의 수렴 판정 같은 수학적 내용은 어려워하지 않으나 무한급수 개념을 부분합의 열을 이용해서 구성하는 것은 어려워한다. 이에 본 연구에서는 무한급수 개념을 구성하는 방법을 APOS 이론과 발생적 분해의 관점에서 부분합 스키마를 이용하여 분석하고자 한다. 질적 연구를 통해 급수 개념의 구성 방법을 점검해서 무한급수 지도 개선에 대한 유용한 교육적 시사점을 얻고자 한다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제7권2호
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• pp.85-99
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• 2003

In this paper, firstly examined various proofs types that cover informal empirical justifications by Balacheff, Miyazaki, and Harel ＆ Sowder and Tall. Using these theoretical frameworks, justification activities by 5th graders were analyzed and several conclusions were drawn as follow: 1) Children in 5th grade could justify using various proofs types and method ranged from external proofs schemes by Harel & Sowder to thought experiment by Balacheff This implies that children in elementary school can justify various mathematical statements of ideas for themselves. To improve children's proving abilities, rich experience for justifying should be provided. 2) Activities that make conjectures from cases then justify should be given to students in order to develop a sense of necessity of formal proof. 3) Children have to understand the meaning and usage of mathematical symbol to advance to formal deductive proofs. 4) New theoretical framework is needed to be established to provide a framework for research on elementary school children's justification activities. Research on proof mainly focused on the type of proof in terms of reasoning and activities involved. But proof types are also influenced by the tasks given. In elementary school, tasks that require physical activities or examples are provided. To develop students'various proof types, tasks that require various justification methods should be provided. 5) Children's justification type were influenced not only by development level but also by the concept they had. 6) Justification activities provide useful situation that assess students'mathematical understanding. 7) Teachers understanding toward role of proof(verification, explanation, communication, discovery, systematization) should be the starting point of proof activities.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
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• pp.410-420
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• 2001

A primitive conceptualization is defined as the set of all intended situations. A non-primitive conceptualization is defined as the set of all the pairs every of which consists of an intended knowledge system and the set of all the situations admitted by the knowledge system. The reality of a domain is considered as the set of all the situation which have ever taken place in the past, are taking place now and will take place in the future. A conceptualization is defined as precise if the set of intended situations is equal to the domain reality. The representation of various elements of a domain ontology in a model of the ontology is considered. These elements are terms for situation description and situations themselves, terms for knowledge description and knowledge systems themselves, mathematical terms and constructions, auxiliary terms and ontological agreements. It has been shown that any ontology representing a conceptualization has to be non-primitive if either (1) a conceptualization contains intended situations of different structures, or (2) a conceptualization contains concepts designated by terms for knowledge description, or (3) a conceptualization contains concept classes and determines properties of the concepts belonging to these classes, but the concepts themselves are introduced by domain knowledge, or (4) some restrictions on meanings of terms for situation description in a conceptualization depend on the meaning of terms for knowledge description.