• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.231-236
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• 2002

By using the infinite dimensional optimization[Jang and Kinoshita(2000)]. which is based on the Hilbert space theory, optimal marine propellers are studied. The mathematical uniqueness for the optimized propeller is shown in this study. As a numerical example, the MAU type propeller is considered and used as the initial guess for the optimization method. The numerical results for an optimal marine propeller is illustrated for the pitch distribution.

• Communications of Mathematical Education
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• v.15
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• pp.29-34
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• 2003

물리학, 공학, 경제학, 생물학, 생태학 등의 자연현상, 사회 현상 그리고 심리상황 등과 관련된 내용들의 모델링 과정을 거쳐 나온 미분방정식의 해를 구하고 해의 의미를 파악하는 작업은 바로 우리의 생활의 진면목을 직접 확인하는 것과 같다. 모델링 과정의 효율성은 교사와 학생간의 충분한 수학적 대화속에서 더욱 의미가 커질 것이다. 아울러 학생들에게 미분방정식의 해의 실제적인 의미를 상상하게 하고 그 결과를 발표하게 하는 것과 해를 구하는 과정에 관한 이론의 이해를 돕는 것이 바람직한 학습 지도 방법이 될 것이다. 전 교육과정을 통해 미분방정식의 모델링 과정을 소개하면서 해의 존재성, 해의 유일성, 해법, 해의 의미 등의 학습 및 지도를 학습자 중심으로 운영할 필요가 있다.

• Journal of KIISE:Software and Applications
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• v.28 no.11
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• pp.833-841
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• 2001

Abstract In this work, we analyze the Levy mutation operations based on the Levy probability distribution in the evolutionary programming via the mean square displacement and the distinctness. The Levy probability distribution is characterized by an infinite second moment and has been widely studied in conjunction with the fractals. The Levy mutation operators not only generate small varied offspring, but are more likely to generate large varied offspring than the conventional mutation operators. Based on this fact, we prove mathematically, via the mean square displacement and the distinctness, that the Levy mutation operations can explore and exploit a search space more effectively. As a result, one can get better performance with the Levy mutation than the conventional Gaussian mutation for the multi-valued functional optimization problems.

• Journal of Ocean Engineering and Technology
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• v.16 no.3
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• pp.28-33
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• 2002

Optimization of marine propellers of constant pitch is studied, with the help of the infinite dimensional optimization (Jang and Kinoshita, 2000a), which is based on the Hilbert space theory. As a numerical example, the MAU type propeller is considered and used as he initial guess for the optimization method. The numerical computations for an optimal marine propeller are performed for the constant pitch distribution. In addition, a new optimization is suggested with the constraint of constant pitch during optimization.

• Journal of KIISE:Information Networking
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• v.32 no.5
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• pp.574-582
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• 2005

Localization in wireless sensor networks is essential to important network functions such as event detection, geographic routing, and information tracking. Localization is to determine the locations of nodes when node connectivities are given. In this paper, centroid approach known as a distributed algorithm is extended to a centralized algorithm. The centralized algorithm has the advantage of simplicity. but does not have the disadvantage that each unknown node should be in transmission ranges of three fixed nodes at least. The algorithm shows that localization can be formulated to a linear system of equations. We mathematically show that the linear system have a unique solution. The unique solution indicates the locations of unknown nodes are capable of being uniquely determined.

• Journal for History of Mathematics
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• v.21 no.3
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• pp.31-52
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• 2008

The concept of infinity, as with other scientific concepts, has a history of evolution. In the present work we intend to discuss the subject matter with regard to Bolzano since he is considered to be the first to accept the idea of actual infinity not just from a metaphysical perspective but from a mathematical one. Like modem platonists, Bolzano defended the infinite set itself regardless of the construction process; this is based on the principal of comprehension and unicity of denotation regarding all concepts. In addition, instead of considering as paradoxical the fact that a one-to-one correspondence existed between an infinite set and its parts, he regarded it in a positive way as a special characteristic. While the Greek era recognized the existence of only one infinity, Balzano acknowledged the existence of various types of infinity and formulated a logical definition for it. The question of infinity is a touchstone of constructive method which holds an increasingly important role in mathematics. The present study stops with just a brief reference to the subject matter and we will leave further in-depth investigation for later.

• Review of KIISC
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• v.33 no.5
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• pp.57-68
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• 2023

최근 클라우드 규제의 변화에 따라 국내 금융권의 클라우드 전환이 확산되면서 주요 인프라로서 클라우드 활용에 관한 연구·개발이 관심을 받고 있다. 2016년도 10월 이전에는 금융회사의 모든 전산시스템에 대하여 물리적 망분리를 적용하여야 하는 등의 과도한 규제로 퍼블릭 클라우드 활용에 어려움이 있었다. 이후 전자금융감독규정이 점차 완화되면서 클라우드 이용이 활성화되고 현재에 이르게 되었다. 안전한 클라우드 이용을 위해서는 금융분야 클라우드 컴퓨팅 서비스 이용 가이드에서 제시하는 업무 연속성 계획 및 출구 전략을 수립하고, 안전성 확보 조치 방안을 마련하며, 클라우드 서비스 제공자의 안전성 평가, 자체 정보보호위원회 심의·의결 및 감독 당국의 보고 등의 내부통제를 준수하여야 한다. 본 고에서는 금융분야의 클라우드 전환 사례 조사를 토대로 전환 동향과 전환 요인, 업권별 특징 및 규제 변화에 대해 살펴보고, 향후 클라우드 이용 환경 변화를 전망해본다.

• Education of Primary School Mathematics
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• v.24 no.2
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• pp.71-81
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• 2021

In this study, I investigate the relationship between mathematics anxiety and mathematics teacher anxiety of elementary school teachers with integrated method. As a result of statistical analysis of the survey of 256 elementary school teachers, there was a statistically significant positive correlation between the two factors (r = .630, p <.05). The analysis show that teaching experience and degree may affect mathematics anxiety and teaching experience, degree, and teacher qualification may affect mathematics teaching anxiety. Subsequently I conduct a qualitative study focusing on interviews with 20 elementary school teachers. As a result of the analysis, I confirm that even if the mathematics anxiety is low, mathematics teaching anxiety may occur due to the teaching environment. As a result of the quantitative and qualitative analysis of this study, Korean elementary school teachers' mathematics anxiety and mathematics teaching anxiety might be regarded as separate factors. From the result of the study, I suggest that mathematics anxiety and mathematics teaching anxiety of elementary school teachers, each emotional state might be considered as independent emotional status. The implication of the study indicate that independent methods might be developed in order to prevent and treat mathematics anxiety and mathematics teaching anxiety in elementary school teachers.

• Communications of Mathematical Education
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• v.33 no.3
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• pp.255-273
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• 2019

In order to help students to understand the essence of prime concepts, this study looked at the history of prime concept development and analyzed how to introduce the concept of textbooks. In ancient Greece, primes were multiplicative atoms. At that time, the unit was not a number, but the development of decimal representations led to the integration of the unit into the number, which raised the issue of primality of 1. Based on the uniqueness of factorization into prime factor, 1 was excluded from the prime, and after that, the concept of prime of the atomic context and the irreducible concept of the divisor context are established. The history of the development of prime concepts clearly reveals that the fact that prime is the multiplicative atom is the essence of the concept. As a result of analyzing the textbooks, the textbook has problems of not introducing the concept essence by introducing the concept of prime into a shaped perspectives or using game, and the problem that the transition to analytic concept definition is radical after the introduction of the concept. Based on the results of the analysis, we have provided several pedagogical implications for helping to focus on a conceptual aspect of prime number.

• Journal of the Korean School Mathematics Society
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• v.14 no.2
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• pp.227-239
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• 2011

The circumcenter of a triangle is introduced in logic geometry part of 8th grade mathematics. To handle certain characteristics of a figure through mathematical proof may involve considerable difficulty, and many students have greater difficulties especially in learning textbook's methods of proving propositions about circumcenter of a triangle. This study compares the methods how the circumcenter of a triangle is explored among the Elements of Euclid, a classic of logic geometry, current textbooks of USA and those of Korea. As a result of it, this study tries to abstract some significant implications on teaching the circumcenter of a triangle.