• Title/Summary/Keyword: 동양수학

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Finite Element Modeling Method for SRM Design (SRM 설계를 위한 유한 요소 모델링 기법)

  • Bae, Jae-Nam;Lee, Sung-Gul;Kim, Won-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.586-592
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    • 2018
  • SRMs are difficult to design using a simple mathematical model and, consequently, numerical analysis based characteristics analysis is used including drive circuits. In this process, it is necessary to analyze the trends according to the change of the design factors, however, many of the design factors affect each other. In order to shorten the design time and achieve a proper design, a modeling technique based on the design parameters is needed. For this purpose, this paper summarizes the formulas employed for shape modeling by minimizing the number of major design factors of the SRM, and proposes a methodology for SRM design using these formulas. In particular, we propose a design method for a 6/4-pole model, one which has been studied for a long time, and showed an example of a design produced by the proposed method.

A Mathematical Model for the Discharge Mechanism of a Metal Hydride Electrode (금속수소 전극의 방전기구에 대한 수학적 모델)

  • Shin, Chee Burm;Hong, Jung Ho;Yun, Kyung Suk;Cho, Byung Won;Cho, Won Il;Jeon, Gui
    • Applied Chemistry for Engineering
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    • v.9 no.5
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    • pp.768-773
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    • 1998
  • A mathematical model of discharge mechanism of metal-hydride (MH) electrode was presented. A computer simulation program was developed in order to predict the variation of electrode potential and the distribution of hydrogen concentration within MH particles during discharge. By investigating the effects of the discharge current density, the size of MH particle, the diffusivity of hydrogen in MH particle, and the porosity of the electrode, it was found that these factors exerted a collective effect on the discharge characteristic of the electrode and the utilization of hydrogen in the MH particle. It was confirmed that and optimization of design factors of an MH electrode is necessary in order to execute a high-rate discharge and to improve the utilization of hydrogen in MH particle.

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저커버그(2004)의 얼굴과 오일러(Euler, 1783)의 두 눈(안(眼))

  • Lee, Mun-Ho
    • The Magazine of the IEIE
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    • v.39 no.7
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    • pp.54-61
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    • 2012
  • 우리 몸에서 가장 중요한 것은 얼굴과 두 눈이고, 아름다움도 얼굴에서 나온다. 세상에서 가장 아름다운 여인으로 서양에서는 클레오파트라(Cleopatra)이고, 동양은 양귀비(楊貴妃, 719~756)를 대표적 예로 든다. 미국 캘리포니아 대학의 Zadeh 교수는 강의 시 휴식시간에 '어느 교수의 부인이 아름다운가?' 라는 농담을 하면서 제일 예쁜 여자는 A그룹, 그 다음은 B 그룹 등으로 구분하는데 착안하여 Fuzzy 개념을 발견(1965)하였고, 그 후 연구계 및 산업체에서 이 이론을 확장해 퍼지세탁기, 퍼지냉장고 등이 가전 시장을 석권한 바 있다. 한편, 2004년 미국 하버드대 기숙사에서 친구와 함께 재미삼아 페이스북을 만든 마크 저커버그(28). 여자친구의 사생활을 여기에 올려 이별의 아픔을 맛보기도 했던 그가 8년 만에 세계적 282억 달러의 부호가 됐다. 세계 인터넷업계가 가슴을 졸이며 기다려온 페이스북의 기업공개(IPO 주식상장)를 통해서다. 1783년 스위스 수학자인 오일러(Euler, 1707~1783) : 학문적으로 방대한 업적을 남긴 만큼 오일러의 인생도 파란만장했다. 그는 20대 초반의 젊은 나이에 병으로 한쪽 눈을 실명하는 불운을 겪기도 했다. 러시아로 돌아간 말년에는 수학문제를 풀기위해서 사흘 밤낮을 꼬박 몰두하다 다른 쪽 시력마저 잃게 된다. 당시 파리아카데미에서는 수여하는 권위 있는 상을 수상하고자 저명한 수학자들도 몇 개월 붙잡는 어려운 문제를 단 사흘 만에 풀었는데 너무나 집중한 나머지 실명한 것이었다. 양쪽 눈을 모두 잃었지만 오일러는 비서에게 자신의 생각들을 받아 적게 하는 방식으로 계속해서 훌륭한 업적을 남겼다. 양 눈(안(眼)) 사이 거리는 6.5cm, 이 시각차가 오늘 3D TV 시대를 열었다. 본고에서는 최근 관심이 고조된 저커버그의 페이스북과 오일러 e에 관해 요약했다.

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A Study on the Quantitative Analysis of Cutting Parameters and Prediction Model for Surface Roughness in Milling (밀링가공에서 표면거칠기에 대한 절삭인자의 정량적 분석과 예측모델에 관한 연구)

  • Jang, Sung-Min;Kang, Shin-Gil
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.3
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    • pp.125-130
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    • 2017
  • In this study, the influence of various factors on surface roughness was investigated using the Taguchi experimental method through high-speed machining processing. Feed rate, pitch, tool diameter, and depth of cut are widely applied to high-speed machining conditions for mold production. Each of these factors was implemented and classified into three levels; then, after high speed machining, surface roughness was measured, the S/N ratio was analyzed, and the influence on the surface roughness of control factors was analyzed quantitatively by ANOVA. Using this information, a mathematical model for predicting surface roughness was derived from multiple regression analysis. This mathematical model enables the surface roughness value after high-speed machining to be predicted at the production stage, before machining, for a wide range of machining conditions.

An Analysis of its Convergence Characteristics and the Adaptive Algorithm for Reducing the Computational Quantities (계산량 감소를 위한 적응 알고리즘 및 수렴특성 분석)

  • 이행우;전만영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.2C
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    • pp.222-228
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    • 2004
  • This paper describes a new adaptive algorithm which can reduce the required computation quantities in the adaptive filter. The proposed adaptive algorithm uses only the signs of the normalized input signal rather than the input signals when coefficients of the filter are adapted. By doing so, there is no need for the multiplications and divisions which are mostly responsible for the computation quantities. To analyze the convergence characteristics of the proposed algorithm, the condition and speed of the convergence are derived mathematically. Also, we simulate an echo canceller adopting this algorithm and compare the performances of convergence for this algorithm with the ones for the other algorithm. As the results of simulations, it is proved that the echo canceller adopting this algorithm shows almost the same performances of convergence as the echo canceller adopting the SIA algorithm.

A Low Density Parity Check Coding using the Weighted Bit-flipping Method (가중치가 부과된 Bit-flipping 기법을 이용한 LDPC 코딩)

  • Joh, Kyung-Hyun;Ra, Keuk-Hwan
    • 전자공학회논문지 IE
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    • v.43 no.4
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    • pp.115-121
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    • 2006
  • In this paper, we proposed about data error check and correction on channel transmission in the communication system. LDPC codes are used for minimizing channel errors by modeling AWGN Channel as a VDSL system. Because LDPC Codes use low density parity bit, mathematical complexity is low and relating processing time becomes shorten. Also the performance of LDPC code is better than that of turbo code in long code word on iterative decoding algorithm. This algorithm is better than conventional algorithms to correct errors, the proposed algorithm assigns weights for errors concerning parity bits. The proposed weighted Bit-flipping algorithm is better than the conventional Bit-flipping algorithm and we are recognized improve gain rate of 1 dB.

Channel Capacity of Mobile Communication System using Switching Repeater (스위칭 중계기를 사용한 이동통신 시스템의 채널용량)

  • Kim, jang-Wook;Choi, Wan;Oh, Chang-Heon;Cho, Sung-Joon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.1
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    • pp.33-39
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    • 2002
  • In mobile communication systems, there are areas where signal coverage is not adequately accomplished by base stations. These areas may be underground parking zones, underground stores, tunnels, and insides of buildings, etc. In these areas, repeaters are broadly used as an economical solution. However, the capacity is decreased as the number of repeaters increases because the noise power that flows to a base station in the reverse link is proportional to the number of repeaters. The reduction of capacity in the reverse link is no longer negligible in the case that several tens or hundreds repeaters are connected to a base station. In this paper, we propose c repeater that is switched off automatically when there is no active user within its coverage. With the switching repeater, we can reduce the unnecessary noise level enhancement when there is no active user within the repeaters coverage. The reverse link capacity of a DS/CDMA system with AOS repeater is analyzed mathematically and compared with that without switching repeater. From the numerical results, noticeable improvement with the switching repeaters is shown.

A Study on the Meaning of Geometric Analysis of Gameun Temple's Taegeuk Shapes (감은사 태극문양의 기하학적 의미 연구)

  • Kim, Il-Hwan;Park, Tae-Bong
    • The Journal of the Korea Contents Association
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    • v.21 no.6
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    • pp.435-444
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    • 2021
  • This paper discusses the geometrical interpretation of the Taegeuk Shapes of Kameun Temple through the geometric analysis of mathematics. Based on the literature, This paper attempted to clarify that the origin of Gameunsa's founding of the spirit of patriotism may coincide with historical records through historical literature and geometric meaning. First, the background of the founding of Kameun temple, geographical location located near the East Sea, especially the history of the ancient Chinese mathematics at the time, And that mathematical knowledge influenced all fields such as agriculture, architecture, and art. Secondly, it is related to the historical record as the space of about 60 centimeters, which is uniquely underground, was identified as the structure of the excavated space. It is thought that there is a strong correlation with the origin that the King Munmu changed into a dragon, and set up the temple to be able to stay. Based on these, the clues of the interpretation of the taegeuk and the triangular pattern were searched in the samcheon yanggi(參天兩地) of the Oriental and circumference of the Western. The taegeuk and triangular patterns represent the symbols of yin-yang harmony, which correspond to the origin of its creation. the Korean people regarded the mysterious dragon as a symbol of yinyang harmony. In conclusion the Shapes of Kameun temple's stone is consistent with the contents mentioned in the historical record.

Study on the ength of the Pitch Pipes Preserved in Korean Sources (동양의 율관에 관한 연구(II) -낙학궤범』소재 율장의 문제점 및 율산에 관한 연구-)

  • 남상숙
    • Journal for History of Mathematics
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    • v.5 no.1
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    • pp.81-95
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    • 1988
  • In Akhakkyebom, one of the greatest Korean Sources, a great mistake was found in the lengths of the pitch pipes. Whanjong from which the other eleven pitches are calculated, is nine inches by decimal system. But the rest are from 9inches by nonary system. To find out how such a contradictory combination could put into so great a book, all the sources available wereexamined. In the process of investigating the numeral change of the lengths of the pitchpipes, it was found that fixation of this contradictory combination was due to the tradiction of Confucianism, which is specialized by its adherence of the old. SongHyon couldn't understand well enough Tsai Yuan-ting's Account of the science of the pitch pipes in Lu-luhsin-shui, Neither could Yi Hye-gu who translated Akhakkwebom into Korean. The parts they misunderstood were pointed out and explained as it should be in this thesis. Several other accounts of the science of the pitch pipes like Chu Tsai-yu's and Jing Farng's are also explained. The Pitch-pipes which were said to have been made by Pak Yon were found out to be of Chu Tsai-yu's. Those which Yi Sang dok wrote were one of Pak Yon's achievements turned out to be of Tsai Yuen-ting's, And othe interesting mistakes were pointed out in thesis thesis. Most of these mistakes were made, I think, because of the lack of the study on the historical background. That's why I tried to examine all the sources available on pitch-pipes. In the lengths of the pitch-pipes preserved in Shih-chi by Ssu-ma Ch'ien, several letters were found to have been misprinted. Some chil's should be “sip” and the letter “il” in Hyopchong should be “chil”. I couldn't deal with all the lengths of the pitch-pipes in this thesis. Especially the real length of the old measure of Whangjong made by PakYon is remained still unknown. I believe a lot more study should be poured on this field to know our traditional music as it was.

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