• Journal of Korean Elementary Science Education
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• v.37 no.2
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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.

• Journal of the Korean Geographical Society
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• v.44 no.3
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• pp.301-322
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• 2009

This paper is an attempt to explore semiotic representations of subway space as the urban machine space of local mobility in terms of space, time and place. For this, the second section of the paper reviews the contours of the urban space of mobility in terms of 'machine space', 'non-place' and 'cognitive map'. The third section interprets the sings of 'spatial' and 'temporal' representations of subway space in Daegu, and suggests the implications of the semiotic representations. It is uncovered that various sign-scapes which coexist in the subway space in coordinated or contradictory ways product the space into multiple and complex techno-social spaces. That is, the spatio-temporal representations of the subway space form the space of 'non-place' on the one hand and the space of 'place' on the other hand, and involve the spatialization of 'memory' on the one hand and the spatialization of 'forgetting' on the other hand. Thus, the subway space should be regarded to be not only the space of 'mobility' which people move in and through, but also the space of 'identity' which has effects on the ways for them to see the machine space and its urban space.

• ETRI Journal
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• v.29 no.5
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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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• v.18 no.1
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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.

• Education of Primary School Mathematics
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• v.12 no.2
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• pp.81-97
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• 2009

Visual representations play an important role for students to understand the meaning of a given problem, devise problem-solving approaches, and implement them successfully. The purpose of this study was to investigate how 6th graders would use visual representations in solving mathematical problems and in what ways such use might affect successful problem solving. The results showed that many students preferred numerical expressions to visual representations. However, students who used visual representations, specifically schematic representations, performed better than those who employed numerical representations. Given this, this paper includes instructional implications to nurture students' use of visual representations in a way to increase their problem solving ability.

• The Pure and Applied Mathematics
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• v.19 no.2
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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 $H_B$.

• Honam Mathematical Journal
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• v.34 no.4
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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 $H_C$.

• Honam Mathematical Journal
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• v.34 no.1
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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 $H_A$.

• Speech Sciences
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• v.8 no.4
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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.

• Journal of The Korean Association For Science Education
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• v.37 no.2
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• pp.253-262
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• 2017

This study aims at investigating the perceptions of science teachers about the role of visual representations in the teaching of electromagnetism, and finding out how science teachers use visual representations in their teaching of electromagnetism and the difficulties they experience in dealing with those representations. A total of 121 science teachers responded to the online survey. The results showed that most of the teachers agreed to the significance of using visual representations in the classroom but regarded their role as means of simply delivering science knowledge rather than constructing or generating knowledge. For the three visual representations widely used in teaching of electromagnetism in secondary schools (electrostatic induction on electroscope, magnetic field around current carrying wire, structure and principle of electric motor), the teachers preferred teacher-centered use of visual representations rather than student-centered and teacher's construction of representations were the most frequent among four types of use; interpretation, construction, application, and evaluation. The difficulties of teaching with these three visual representations were categorized into several factors; teachers, students, the characteristics of the representations, and lack of resources and classroom environment. Teachers' limited perceptions about the role of visual representations were associated with the ways of using visual representations in their teaching. Implications for the effective use of visual representations for science learning and teaching were discussed.