• 한국초등과학교육학회지:초등과학교육
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• 제37권2호
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• pp.219-231
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• 2018

This study surveyed the elementary school teachers' use of visual representations and their perceptions of the functions of visual representations in the teaching of electricity unit. A total of 110 elementary teachers who have experiences in teaching electricity unit responded to online survey. The result showed firstly that most of the teachers use visual representations in their teaching and it is mostly limited to those presented in textbooks or images that they can get easily from internet search. Secondly, elementary teachers thought that they have high ability in using visual representations and low ability in understanding students' visual presentation ability. Thirdly, visual representations are more often preferred to be used as teacher-centered ways than student-centered ways for motivating students and conceptual understanding. However, in case of scientific inquiry, both teacher-centered and student-centered ways were equally preferred. Lastly, the teachers' perceptions of the functions of visual representations were categorized into 'teaching-instrumental function', 'learning-instrumental function', 'communicative-instrumental function' and 8 subcategories were found. The most frequent function was the 'information delivery function' in the 'teaching-instrumental function' category. Implications for teacher education and further studies were discussed.

• 대한지리학회지
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• 제44권3호
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• pp.301-322
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• 2009

본 논문은 국지적 이동성의 도시 기계 공간인 지하철 공간의 기호적 재현을 공간, 시간, 장소의 의미에서 탐구한다. 제2절은 기존 연구에서 제시된 이동성의 도시 공간의 전반적 특징을 '기계 공간', '(비-)장소', '인지 지도'의 개념을 중심으로 검토한다. 제3절은 대구 지하철 공간에 대한 '공간적' 및 '시간적' 재현의 기호들을 해석하고, 그 기호적 재현의 의미를 제시한다. 이를 통해 지하철 공간에 상호 조화적으로 혹은 모순적으로 공존하는 기호 경관들이 그 공간을 다중적, 복합적인 기술-사회 공간으로 생산한다는 것을 밝힌다. 지하철 공간의 공간적-시간적 재현은 한편으로는 '(비-)장소', 다른 한편으로는 '장소'의 공간을 형성하며 또한 한편으로는 '기억', 다른 한편으로는 '망각'의 공간화를 수반한다. 지하철 공간은 사람들이 이동하는 '이동성' 의 공간만이 아니라 기계 및 도시 공간을 바라는 방식에 영향을 주는 '정체성'의 공간으로 생각되어야 한다.

• ETRI Journal
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• 제29권5호
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• pp.619-632
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• 2007

Side channel attacks are a very serious menace to embedded devices with cryptographic applications. To counteract such attacks many randomization techniques have been proposed. One efficient technique in elliptic curve cryptosystems randomizes addition chains with binary signed digit (BSD) representations of the secret key. However, when such countermeasures have been used alone, most of them have been broken by various simple power analysis attacks. In this paper, we consider combinations which can enhance the security of countermeasures using BSD representations by adding additional countermeasures. First, we propose several ways the improved countermeasures based on BSD representations can be attacked. In an actual statistical power analysis attack, the number of samples plays an important role. Therefore, we estimate the number of samples needed in the proposed attack.

• East Asian mathematical journal
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• 제18권1호
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• pp.75-84
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• 2002

The third important Euler-Mascheroni constant $\gamma$, like $\pi$ and e, is involved in representations, evaluations, and purely relationships among other mathematical constants and functions, in various ways. The main object of this note is to summarize some known series representaions for $\gamma$ with comments for their proofs, and to point out that one of those series representaions for $\gamma$ seems to be incorrectly recorded. A brief historical comment for $\gamma$ is also provided.

• Kyungpook Mathematical Journal
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• 제64권3호
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• pp.395-405
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• 2024

In this paper we define a matrix sequence called the Pell matrix sequence whose elements consist of Pell numbers. Using a positive parameter k, we generalize the Pell matrix sequence to a k-Pell matrix sequence and using two parameters s, t we generalize them to (s, t)-Pell matrix sequences. We give the basic properties of these matrix sequences. Then, using these properties we obtain exponential representations of the Pell matrix sequence and its generalizations in different ways.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제12권2호
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• pp.81-97
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• 2009

수학 문제를 해결하는 과정에서 시각적 표현을 적절히 활용하면 문제의 의미를 보다 확실히 이해할 수 있고 궁극적으로 문제를 해결할 가능성을 높인다. 본 연구는 6학년 학생들을 대상으로 수학 문제를 해결할 때 시각적 표현을 얼마나 사용하는지, 어떤 유형을 어떻게 활용하는지, 그리고 이런 시각적 표현의 사용 및 유형과 문제해결과의 관계는 어떠한지 분석하였다. 연구 결과, 많은 학생들이 시각적 표현보다는 수식을 사용하는 경우가 많았던 반면에, 시각적 표현을 사용한 경우가 그렇지 않은 경우보다 성공률이 높게 나타났다. 시각적 표현 중에서도 도식 표현을 사용한 학생들이 성공적인 문제 해결에 도달할 수 있었다. 이러한 연구 결과를 바탕으로 본 논문은 수학 문제 해결에서의 시각적 표현의 중요성과 그에 대한 지도 방향에 시사점을 제공한다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제19권2호
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• pp.137-145
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• 2012

While investigating the Lauricella's list of 14 complete second-order hypergeometric series in three variables, Srivastava noticed the existence of three additional complete triple hypergeometric series of the second order, which were denoted by $H_A$, $H_B$ and $H_C$. Each of these three triple hypergeometric functions $H_A$, $H_B$ and $H_C$ has been investigated extensively in many different ways including, for example, in the problem of finding their integral representations of one kind or the other. Here, in this paper, we aim at presenting further integral representations for the Srivatava's triple hypergeometric function $H_B$.

• 호남수학학술지
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• 제34권4호
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• pp.473-482
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• 2012

While investigating the Lauricella's list of 14 complete second-order hypergeometric series in three variables, Srivastava noticed the existence of three additional complete triple hypergeo-metric series of the second order, which were denoted by $H_A$, $H_B$ and $H_C$. Each of these three triple hypergeometric functions $H_A$, $H_B$ and $H_C$ has been investigated extensively in many different ways including, for example, in the problem of finding their integral representations of one kind or the other. Here, in this paper, we aim at presenting further integral representations for the Srivatava's triple hypergeometric function $H_C$.

• 호남수학학술지
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• 제34권1호
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• pp.113-124
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• 2012

While investigating the Lauricella's list of 14 complete second-order hypergeometric series in three variables, Srivastava noticed the existence of three additional complete triple hypergeometric series of the second order, which were denoted by $H_A$, $H_B$ and $H_C$. Each of these three triple hypergeometric functions $H_A$, $H_B$ and $H_C$ has been investigated extensively in many different ways including, for example, in the problem of finding their integral representations of one kind or the other. Here, in this paper, we aim at presenting further integral representations for the Srivatava's triple hypergeometric function $H_A$.

• 음성과학
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• 제8권4호
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• pp.243-257
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• 2001

In English textbooks, there are three kinds of English intonation representations: Trager & Smith's, Weak-strong, Audio-lingual way. Each representation has its merits and demerits. Therefore, just one of them is insufficient to represent English intonation properly. Trager & Smith's representation is relevant to show holistic intonation itself. In contrast to this merit, it is not appropriate to represent downstep, declination, etc. With Weak-strong, it is good to show weak and strong point in the sentence. It is not, however, consistent with intonation. Instead of these representations, some textbooks accept Audio-lingual method. Audio-lingual method gives students more chances to hear native speakers' intonations. But it doesn't give ways to understand English intonation itself. In English textbooks, they don't have any hierarchies dependent upon students' proficiency. In spite of various intonations, they just accept a few limited intonation models. Thus, it is necessary to review all kinds of intonation representations and to develop more advanced and relevant English intonation representation.