• Journal of applied mathematics & informatics
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• 제5권1호
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• pp.141-152
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• 1998

Based on the geometric representation an efficient al-gorithm is designed to find all articulation points of a permutation graph. The proposed algorithm takes only O(n log n) time and O(n) space where n represents the number of vertices. The proposed se-quential algorithm can easily be implemented in parallel which takes O(log n) time and O(n) processors on an EREW PRAM. These are the first known algorithms for the problem on this class of graph.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제6권2호
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• pp.75-84
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• 2002

Using good properties of an optimal normal basis of type I in a finite field ${\mathbb{F}}_{2^m}$, we present a design of a bit serial multiplier of Berlekamp type, which is very effective in computing $xy^2$. It is shown that our multiplier does not need a basis conversion process and a squaring operation is a simple permutation in our basis. Therefore our multiplier provides a fast and an efficient hardware architecture for a bit serial multiplication of two elements in ${\mathbb{F}}_{2^m}$.

• Journal of applied mathematics & informatics
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• 제5권2호
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• pp.277-284
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• 1998

The reliability and an estimate for it are derived for series-parallel and parallel-deries stress-strength model under assumption that all components are subjected to a common stress. We also obtain the asymptotic normal distribution of the estimate.

• 대한수학교육학회지:학교수학
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• 제2권2호
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• pp.357-388
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• 2000

This study aims to develop performance assessment tools for mathematics in the primary school. In order to achieve this aim, it reviews the tics in the primary school. In order to achieve this aim, it reviews the meaning and the purpose of mathematics performance assessment, and the characteristics of performance assessment tasks. Then the framework for portfolio developed in this study is introduced. This portfolio is called 'mathematical thinking and applying'. It aims at balanced assessment for improvement of mathematics instruction. It is composed of journal writhing, problem by the student, constructed task, work samples, written test, self assessment, teacher's comment and parents' comment. The criteria of performance tasks is categorized in impact, reasoning, accuracy and communication. The procedures of development of these tasks are as follows: the analysis of mathematics curriculum for the primary school, the design of performance tasks with considering teaching unit goals, designing rubrics, discussing these tasks with teachers in primary school, modifying them when is needed, observing the process of children's task performing, interviewing with teachers and final modifying. After performance assessment tasks are implemented, the answers by the students is analyzed using rubrics. Then anchor papers are selected. Also, the errors of children are analyzed. Through the process, teachers can obtain the information of children for improvement of mathematics instruction. Finally in order to generalize this study, I suggest that we need to cooperate with the field of education and to establish expert assessment groups.

• Journal of applied mathematics & informatics
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• 제8권2호
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• pp.387-401
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• 2001

If the distance between two vertices becomes longer after the removal of a vertex u, then u is called a hinge vertex. In this paper, a linear time sequential algorithm is presented to find all hinge vertices of an interval graph. Also, a parallel algorithm is presented which takes O(n/P + log n) time using P processors on an EREW PRAM.

• Korean Journal of Mathematics
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• 제25권4호
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• pp.513-535
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• 2017

As a continuation to the study in [8, 12, 15, 17], we construct bi-conservative central normal (BCN) and bi-conservative asymptomatic normal (BAN) ruled surfaces in Euclidean 3-space ${\mathbb{E}}^3$. For such surfaces, local study is given and some examples are constructed using computer aided geometric design (CAGD).

• Journal of Mechanical Science and Technology
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• 제16권5호
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• pp.619-632
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• 2002

In recent study on design of experiments, the complicate metamodeling has been studied because defining exact model using computer simulation is expensive and time consuming. Thus, some designers often use approximate models, which express the relation between some inputs and outputs. In this paper, we review and compare the complicate metamodels, which are expressed by the interaction of various data through trying many physical experiments and running a computer simulation. The prediction model in this paper employs interpolation schemes known as ordinary kriging developed in the fields of spatial statistics and kriging in Design and Analysis of Computer Experiments (DACE) model. We will focus on describing the definitions, the prediction functions and the algorithms of two kriging methods, and assess the error measures of those by using some validation methods.

• Korean Journal of Mathematics
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• 제25권3호
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• pp.405-435
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• 2017

We deal with a sensitivity analysis of an optimal shape control problem for the stationary Navier-Stokes system. A two-dimensional channel flow of an incompressible, viscous fluid is examined to determine the shape of a bump on a part of the boundary that minimizes the viscous drag. By using the material derivative method and adjoint variables for a shape sensitivity analysis, we derive the shape gradient of the design functional for the model problem.

• 한국수학사학회지
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• 제20권4호
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• pp.61-70
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• 2007

인류의 문명은 수학적 관찰과 사고의 결과를 정립하고 삶과 자연에 대한 인식과 인식방법을 깨우쳐가며 시작되었다. 수학은 이집트와 이라크(메소포타미아) 등의 중동 지역의 문명에 논리적 사고를 일깨운 그리스-로마 문명이 합쳐지면서 크게 기하학과 대수학의 흐름을 타고 발전하여 왔다. 수학은 다양한 분야로 분파되기도 하고 다시 합쳐지는 과정을 반복하며 발전을 거듭하면서 결국 현대문명의 기반과 토대를 형성하였다. 서양 문명의 역사는 실로 수학의 역사인 것처럼 인식되기도 한다. 20세기 말, 컴퓨터의 발달과 함께 수학에서도 새로운 분야가 태동하여 큰 발전을 보았는데, 이 분야가 이산수학 또는 조합수학이라는 이름으로 불리는 수학이다. 조합수학은 '21세기의 수학'이라는 별칭을 가질 만큼 활성적인 연구 분야로 자리를 잡아가고 있으며 교육적 차원의 중요성도 부각되고 있다. 본 논문에서는 조합수학의 발생을 엿볼 수 있는 흥미로운 문제들을 훑어보며 조합수학의 유래와 의미를 논하고자 한다.

• 대한수학교육학회지:수학교육학연구
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• 제12권3호
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• pp.389-408
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• 2002

This paper is based on a teaching experiment research conducted in a differential equations course at Ewha Womans University. The purpose of this paper lies in seeking a new direction in the teaching and learning of college mathematics by applying RME's theoretical essence to the teaching of differential equations. For this purpose, the emergent procedure had to be carefully considered before to analyzing the existing problems in teaching differential equations and alternative access to reformed differential equations. Methods of developmental research, ideas concerning teaching procedure and instructional design are offered. This research demonstrates that a deeper understanding of differential equations by students can be achieved with the instructional design which reflects the RME theory.