• International Journal of Automotive Technology
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• v.2 no.1
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• pp.17-23
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• 2001

Measurements of the initial values lead to an inverse and mathematically unprecisely formulated problem. A precise definition of an inverse problem is possible. It is to state a mathematical model of a physical process with clearly defined initial and exit values for the system behind the process. One can grasp the idea of an inverse problem by considering the tire as a copy of the objects of nature in a room with observations. Interpretation of nature is generally a result of an inverse problem. On one hand, the tire may be represented through the sensory organs and the nervous system as well as the experiences of the developer's existing apparatus of the projection of reality. On the other hand, it may be represented by a physical law or a model that can be confirmed or is to be refuted with the help of suitable measurements. During reconstruction of a measuring signal and the identification of a black box that can be assumed to be linear and causal, the tire becomes a first type Volterra integral equation of the convolution type. But measurements of the initial values are always fuzzy, the errors grow and the system behavior can no longer be forecasted. Thus, we have to deal with a chaotic system. This chaos produces fractals in a natural way. These are self-similar geometric structures. This self-similarity is clearly visible in the design.

• Bulletin of the Society of Naval Architects of Korea
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• v.20 no.3
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• pp.17-20
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• 1983

There have been many investigations of predicting the added resistance of a ship in seaway since Havelock discussed this topic in 1937. Among these researches, Maruo's theoretical approach is known as the most consistent mathematical representation for added resistance of a ship in regular head sea. In his theory, the hull form of a ship is represented under the slender body approximation. But the motion responses which were used for the calculation of the added resistance have been obtained by using the strip method which is based on an approximation that the hull form may be expressed as set of two dimensional cylinder sections in longitudinal direction. Therefore two different methods for hull form representation were implicity used in Maruo's original work for the added resistance calculation. Utilizing the characteristics that hull forms are usually slender, Kan expressed the hull form as two dimensional cylinder at each station by using the Taylor series expansion for the length wise direction. Putting this idea into Maruo's original work, the added resistance can be obtained with the explicitly unique representation of the hull form. For the purpose of comparison the added resistance of a hull form(series 60, Cb=0.6) was calculated by using the motion response obtained by Shintani. The numerical result showes a good qualitative agreement with the experimental result by Sibul.

• Education of Primary School Mathematics
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• v.21 no.2
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• pp.193-208
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• 2018

Classification is presented in the curriculum of elementary school mathematics, science, Korean language, and integrated subjects as the major function that needs to be learned. In addition, mathematics textbooks teach the classification as a basic process for organizing and interpreting collected materials in a separate unit. So, we analyzed the curriculum documents and textbooks of mathematics, science, Korean language, and integrated subjects. And we explored how to teach the classification in the context of mathematics subject. As a result, it is necessary to find different classification criteria in conjunction with detailed observation and investigation activities, and to teach that considering the circumstances and purpose of the classification. It also provided implications on how to revive converged classes that focus on big ideas and skills, which are commonly offered by various subjects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7A
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• pp.725-733
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• 2006

In this paper, we propose an algorithm which makes the frequency of output signal synchronize with frequency of input signal in Equalization Digital On-channel Repeater (EDOCR) system which was proposed to overcome the disadvantage of conventional Digital On-Channel Repeater (DOCR). Also, we verify the algorithm by using the mathematical equivalent model and analysis the performance by implying the algorithm to EDOCR. The main idea is to use the frequency offset information, which comes from carrier recovery in the receiving part of EDOCR, when the demodulated symbol is re-modulated in transmitting part. Based on the proposed algorithm, EDOCR not only makes the output signal synchronized with input signal in frequency but also emit the output signal which satisfies the ATSC transmission standard without additional equipments such as Global Positioning System (GSP).

• Korean Journal of Logic
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• v.5 no.1
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• pp.147-157
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• 2001

In this study I try to show some numerical analogy between Leibniz's binary system anc I-ching's symbolic system of duo rerum principia, imagines quator, octo figurae am 64 hexagrams. But, there is really a formal logical accordance in their symbolic foundations, on which are based especially the Wittgenstein's 16 truth-tables in his Tractatus-logico-philosophicus(5.101) am 16 hexagrams, as long as we interpret with the binary values 0 am 1, i.e. the Bi-Polarity, the logical tradition from J. Boole, G. Frege through B. Russell and AN. Whitehead to R. Wittgenstein. So, I argue that the historical and theoretical root of that tradition goes back to the debate between Bouvet and Leibniz about the mathematical structure of I-ching' symbols and the Leibnizian binary arithmetic. In the letter on 4. 11. 1701 from Peking to Leibniz, Bouvet wrote that the I-Ching's symbolism has an analogous structure with Leibniz's binary arithmetic. Corresponding to his suggestion, but without exact knowledge, in the letter of 2. January 1967 to the duke August in Braunschweig-Lueneburg-Wolfenbuettel had Leibniz shown already an original idea for the creation of the world with imago Dei which comes from binary progression, dark and light on water.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.325-328
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• 2009

In this study, A Magnetic stimulation Pulse Train control technique is introduced and applied to Flyback converter operating in discontinuous conduction mode. In contrast to the conventional pulse width modulation control scheme, the principal idea of a Magnetic stimulation Pulse Train is to achieve output voltage regulation using high and low power pulses. The proposed technique is applicable to any converter operating in discontinuous conduction. However, this work mainly focuses on Flyback topology. In this paper, the main mathematical concept of the new control algorithm is introduced and simulations as well as experimental results are presented.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.4
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• pp.95-102
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• 2018

In this study, existential thoughts in Frank Lloyd Wright's notion of nature were investigated. Wright, a modern architect, presented the idea of creating organic architecture in harmony with nature. His naturalistic romanticism is considered to be the original inspiration for his concept of organic architecture. However, his understanding of architecture in harmony with nature stems from existential ideas in his notion of nature, including humanity. The proposed study analyzes his existential beliefs through his speeches and writings in four categories-love of nature, thoughts of abstract and concrete, nature as being intrinsic and "becoming," and thoughts on science and art. Our analyses reveal that, on the one hand, Wright was inspired by thoughts of naturalistic romanticism born from his disillusionment with city life and an urge to seek life in nature, while, on the other, he also believed that real nature is intrinsic to humans and manifests itself in the very core of their being. He sought to unite humanity, as the interior of nature, with its physical environment, as the exterior of nature. His notion of nature is a "becoming" one that changes with time and space, and varies based on individual humans. In line with these thoughts, Wright sought to create forms not only with respect to mathematical dimensions, but also in consideration of human significance. He considered art and architecture to be born out of an integral thought as a process of humanization. To him, nature is interpreted by humans.

• The Mathematical Education
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• v.59 no.2
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• pp.147-166
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• 2020

Textbooks are important resources in support of teaching and learning mathematics competencies which are emphasized in the most recently revised mathematics curriculum. This study analyzed how six mathematics competencies and their sub-elements are implemented in the mathematics textbooks for the fifth and sixth grades. A total of 465 activities or items in the targeted textbooks were analyzed. The findings of this study showed that both the communication competence and the reasoning competence were the most frequent competencies, followed by the problem solving competence. In contrast, the other three competences (i.e., creativity and integration, attitude and practice, and information processing) were less popular. Detailed analyses of sub-elements according to each competence revealed that one or two specific sub-elements were emphasized within a competence. Whereas "expressing one's idea" was the most prevalent sub-element in the communication competence, both "analyzing mathematical facts" and "observation and conjecture" were the most frequent in the reasoning practice. Specific sub-elements were jointly implemented within or across competences. "External connections of mathematics and integration" in the creativity and integration competence was carried out in relation to "recognition of values" in the attitude and practice competence. This paper also included some examples of activities or items showing how specific sub-elements of each competence were reflected on. This study is expected to provide implications on how to implement mathematics competencies throughout the textbooks.

• Journal of The Korean Association For Science Education
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• v.34 no.4
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• pp.335-347
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• 2014

Size/scale is a central idea in the science curriculum, providing explanations for various phenomena. However, few studies have been conducted to explore student understanding of this concept and to suggest instructional approaches in scientific contexts. In contrast, there have been more studies in mathematics, regarding the use of number lines to relate the nature of numbers to operation and representation of magnitude. In order to better understand variations in student conceptions of size/scale in scientific contexts and explain learning difficulties including alternative conceptions, this study suggests an approach that links mathematics with the analysis of student conceptions of size/scale, i.e. the analysis of mathematical structure and reasoning for a number line. In addition, data ranging from high school to college students facilitate the interpretation of conceptual complexity in terms of mathematical development of a number line. In this sense, findings from this study better explain the following by mathematical reasoning: (1) varied student conceptions, (2) key aspects of each conception, and (3) potential cognitive dimensions interpreting the size/scale concepts. Results of this study help us to understand the troublesomeness of learning size/scale and provide a direction for developing curriculum and instruction for better understanding.

• Journal of architectural history
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• v.18 no.6
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• pp.65-84
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• 2009

This study was to analyze the philological character of Huangdizhaijing(黃帝宅經). Huangdizhaijing is a first stage scriptures of YangzhaiFengshui(陽宅風水) which is the firstly mentioned book in Sikuquanshu(四庫全書). Huangdizhaijing is an obligatory book to read to understand the palace of ancient dynasty as well as general housing of people. Huangdizhaijing measured housing conditions divided into Yangzhai(陽宅) and Yinzhai(陰宅). The contents succeeded traditional Yangzhaiguan(陽宅觀) which values direction(方向) and Jiri(吉日). Thatis, classifying Yangzhai into 24 directions based on Qi of YinYang(陰陽之氣) theory, general contents of Huangdizhaijing explains regulatory rules and propitious day in accordance with the Yangzhai mathematical principles and archaeology through Jixiongshenshalun(吉凶神煞論). Huangdizhaijing includes the kernel of understanding the chinese architect system and housing culture because it describes close reciprocal influences between man and house. It seems that the author of Huangdizhaijing is not the emperor but he was represented by descendants who systemized the idea of Huangdizhaijing in Yangzhai shu(陽宅書). Being there many of documents presented by emperor like Huangdineijing(黃帝內徑), It is counted that the reason of the representing emperor is to show off its origin has long and authoritative history. It seems that the preserved period of writing Huangdizhaijing is Tang(唐) dynasty, but counting that various Yangzhaishu prevailed, Huangdizhaijing's contents has much in common with Dunhuangben(敦煌本), and it valued Menfazhidu(門閥制度) of Weijinnanbeichao(魏晉南北朝) dynasty, the many of the contents of Huangdizhaijing should be formed before Tang dynasty. The exiting editions of Huangdizhaijing could be divided into generally 8 kinds:(1) Zhengtongdaocangben(正統道藏本) (2)Yimenguangduben(夷門廣牘本) (3)Jindaimishuben(津逮秘書本) (4)Shuofuben(說?本) (5)Gujintushujichengben(古今圖書集成本) (6) Sikuquanshuben(四庫全書本) (7)Xuejintaoyuanben(學津討原本) (8)Dunhuangben(敦煌本).