• Title, Summary, Keyword: 대칭성

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A development of low frequency electrical nerve stimulator for muscle care and diet (저주파를 이용한 신경자극 치료장치 개발)

  • 정영수;현웅근
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.462-466
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    • 2002
  • This paper describes a low frequency electrical nerve stimulator for muscle care. The developed system consist of 8bit low power consumed MPU, voltage boosting circuit converting 9V input to 120V output, repairing circuit for distorted output pulse, LED and buttons for I/O, and electro-chemical pad. The pulse generation algorithm for the muscle care effect is developed with basic pulses such as a single phase rectangle pulse, symmetric rectangle pulse, and depolarized interrupt pulse.

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Problem solving and teaching 'group concept' from the point of symmetry (대칭성' 관점에서 본 '문제해결' 및 '군' 개념지도)

  • 남진영;박선용
    • Journal of Educational Research in Mathematics
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    • v.12 no.4
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    • pp.509-521
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    • 2002
  • The purpose of this paper is as follows: $^{\circleda}$ to disclose the essence of symmetry $^{\circledb}$ to propose the desirable strategy of problem-solving as to symmetry $^{\circledc}$ to clarify the relationship between symmetry and group $^{\circledd}$ to propose a way of introduction of 'group' in school mathematics according to its fundamental characteristic, symmetry. This study shows that the nature of symmetry is 'invariance under a transformation' and symmetry is the main idea of 'group'. In mathematics textbooks and mathematics education literature, we find out that the logic of symmetry is widespread. We illustrate two paradigmatic problem related to symmetrical logic and exemplify a desirable instruction of Pascal's triangle. This study also suggests a possibility of developing students' unformal and unconscious conception of group with sym metry idea from elementary to secondary school mathematics.

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The far-field characteristics of the dipole mode laser in the two dimensional single cell photonic crystal (2차원 단일 결함 광결정에서 이중 극자 모드 레이저의 먼 장 특성)

  • 김선경;김세헌;김국현;이용희
    • Proceedings of the Optical Society of Korea Conference
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    • pp.238-239
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    • 2003
  • 2차원 슬랩 형태의 단일 결함 레이저는 낮은 발진 문턱값과 작은 모드 부피로 인해 문턱 없는 레이저의 동작 가능성, 광자 집적 회로에서의 광원 소자 등으로 각광을 받고 있다. 광결정은 결정 구조에 따라 삼각격자와 사각격자로 나눌 수 있는데, 특히 삼각격자의 경우 사각격자에 비해 밴드갭이 보다 넓은 주파수 영역에 걸쳐 나타나므로, 공진기와 도파로서의 응용에 더 적합한 소재로 연구되고 있다. 2차원 삼각구조 단일 결함 광결정은 60$^{\circ}$회전에 대하여 대칭성을 가지므로, 군론에 따라 기본적으로 60$^{\circ}$,120$^{\circ}$,180$^{\circ}$,360$^{\circ}$의 회전 대칭성을 가지고 있는 네 종류의 모드가 존재한다. (중략)

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Superspace Symmetry of the Incommensurate Phase in Barium Sodium Niobate ($Ba_2NaNb_5O_{15}$에서의 Inocmmensurate상의 초공간 대칭성)

  • Kim, Hyo-Jin;Lee, Jeong-Yong;Ju, Ung-Gil
    • Korean Journal of Crystallography
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    • v.1 no.1
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    • pp.1-7
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    • 1990
  • It is shown that the symmetry of the incommensurate phase in Ba2NaNb5O15(BSH) belongs to the four dimensional superspace group C from an analysis of the systematic extinction or the rxtra reflections due to the incommensllrate structure. The resulting superstructure is characterizetl by the space group Ima2(C3l) and the origin of the incommensurability in BSN is briefly discussed. Especially. HREM image have shown the prrscnce of discommensurations. In addition. a group-theoretical consideration of structural phase transitions in BSN is suggested.

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Vehicle Detection Scheme Based on the Symmetry of Horizontal and Vertical Edge Features (수평 및 수직 에지 성분의 대칭성 기반 차량 검출 기법)

  • Han, Sung-Ji;Chung, Hwan-Ik;Hahn, Hern-Soo
    • Proceedings of the KIEE Conference
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    • pp.1851_1852
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    • 2009
  • 본 논문은 차량 영역에 나타나는 수평, 수직 에지 특성만을 이용하여 빠르고 효율적으로 차량을 검출하는 방법을 제안한다. 차량을 포함하는 입력영상의 긴 수직 에지 성분을 찾아 차량의 후보 영역을 결정한다. 영상의 에지 성분의 누적 대신 연속적으로 나타나는 긴 수직 에지 성분을 찾음으로써 차량의 후보 영역의 검출과 동시에 중요한 정보를 담고 있는 도로와 접하는 차량의 하단부를 함께 검출한다. 후보 영역 내에서 차량과 비 차량을 구분하는 검증 단계에서는 차량의 후면의 대칭성(Symmetry)을 이용하여 후보 영역 내에서 차량이 있을 가능성이 있는 바닥 점 위에서 좌측과 우측의 유사도(Matching rate)를 이용하여 차량과 비 차량을 판별한다. 기존의 템플릿 기반 방법이나 외관 기반 방법이 아닌 에지 성분만을 이용하여 후보 영역을 결정하고 검증하기 때문에 다른 검출 기법들에 비해 비교적 검출 시간이 짧고 실시간 차량 검출에 적합하다.

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A study on the electrical characteristics with the electrode symmetry of a disk-type piezoelectric transformer (디스크형 압전 변압기의 전극 대칭성에 따른 전기적 특성)

  • Lee, Jong-Pil
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.2
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    • pp.835-840
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    • 2011
  • In this study, a disk-type piezoelectric transformer was fabricated. Its diameter was 50 mm and thickness was 4.5 mm. The driving and generating electrode with their gap of 1mm were fabricated on the top surface. But the common electrode was fabricated on the whole bottom surface. The electrode surface of driving and generating part on the top surface was divided into 2, 4 and 8 pieces. The electrical characteristics with its electrode variation was measured in the range of load resistance of $100{\Omega}{\sim}10_{K\Omega}$. We investigated quantitively the influence of the set-up voltage ratio.

A Case of Symmetrical Lipomatosis Limited of the Tongue (혀에 국한하여 발생한 대칭성 지방종증 1예)

  • Jeong, Se Won;Nam, Jae Sung;Kie, Jeong Hae;Shin, Hyang Ae
    • Korean Journal of Head & Neck Oncology
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    • v.31 no.2
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    • pp.58-62
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    • 2015
  • Benign symmetric lipomatosis, also known as Madelung's disease, Launois-Bensaude syndrome and multiple symmetric lipomatosis is a cutaneous condition characterized by extensive symmetric fat deposits in the neck, shoulders, and upper trunk. But symmetrical lipomatosis of the tongue is very rare and characterized by involvement exclusively of the tongue, invasiveness, and absence of encapsulation of the adipose tissue. A 75-year-old man presented with about a year history of painless tongue masses on both lateral border. Bilateral partial glossectomy was performed and subsequently was confirmed as symmetrical lipomatosis pathologically. We report this case with a review of the literatures.

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Cosmetic Results of Conservative Treatment for Early Breast Cancer (조기유방암에서 유방보존수술 및 방사선치료후의 미용적 결과)

  • Kim Bo Kyoung;Shin Seong Soo;Kim Seong Deok;Ha Sung Whan;Noh Dong-Young
    • Radiation Oncology Journal
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    • v.19 no.1
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    • pp.21-26
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    • 2001
  • Purpose : This study was peformed to evaluate the cosmetic outcome of conservative treatment for early breast cancer and to analyze the factors influencing cosmetic outcome. Materials and Methods : From February 1992 through January 1997, 120 patients with early breast cancer were treated with conservative surgery and postoperative radiotherapy. The types of conservative surgery were quadrantectomy and axillary node dissection for 108 patients $(90\%)$ and lumpectomy or excisional biopsy for 10 patients $(8.3\%)$. Forty six patients $(38\%)$ received adjuvant chemotherapy (CMF or CAF). Cosmetic result evaluation was carried out between 16 and 74 months (median, 33 months) after surgery. The cosmetic results were classified into four categories, i.e., excellent, good, fair, and poor. The appearances of the patients' breasts were also analyzed for symmetry using the differences in distances from the sternal notch to right and left nipples. A logistic regression analysis was performed to identify independent variables influencing the cosmetic outcome. Results : Cosmetic score was excellent or good in $76\%$ (91/120), fair in $19\%$ (23/120) and poor in $5\%$ (6/120) of the patients. Univariate analysis showed that tumor size (T1 versus T2) (p=0.04), axillary node status (N0 versus N1) (p=0.0002), extent of surgery (quadrantectomy versus lumpectomy or excisional biopsy) (p=0.02), axillary node irradiation (p=0.0005) and chemotherapy (p=0.0001) affected cosmetic score. Multivariate analysis revealed that extent of surgery (p=0.04) and chemotherapy (p=0.0002) were significant factors. For breast symmetry, univariate analysis confirmed exactly the same factors as above. Multivariate analysis revealed that tumor size (p=0.003) and lymph node status (p=0.007) affected breast symmetry. Conclusion : Conservative surgery and postoperative radiotherapy resulted in excellent or good cosmetic outcome in a large portion of the patients. Better cosmetic results were achieved generally in the group of patients with smaller tumor size, without axillary node metastasis and treated with less extensive surgery without chemotherapy.

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중전기의 설계에 따른 전계, 자계, 분포특성해석을 위한 기본이론의 적용방법(상)

  • 임달호
    • JOURNAL OF ELECTRICAL WORLD
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    • no.4
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    • pp.30-37
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    • 1984
  • 본연구는 전기기기의 설계시에 필요한 자료가 되는 전계, 자계 분포특성을 해석하기 위하여 수치해석법의 한 방법인 유한요소법을 적용한 것으로서, 전기기기를 변압기, 직류기, 동기기 및 유도기로 대별하여 각각의 해석 모델을 선정하고 또한 이에 대한 대칭성 및 주기성을 고려하여 2차원의 해석영역을 결정하였으며 전자계의 기본방정식으로부터 이 해석모델을 해석하기 위한 모델방정식을 유도하였다.

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