• Title/Summary/Keyword: 이심

Search Result 212, Processing Time 0.024 seconds

The Optimization Design of Rotor Slot shape in Outer-Rotor Type Induction Motor For Fan Blowers (송풍 팬을 위한 외전형 유도전동기의 회전자 슬롯형상의 최적화)

  • Kim, Kyung-Su;Cha, Hyun-Rok;Yun, Cheol-Ho;Jung, Tae-Uk
    • Proceedings of the KIEE Conference
    • /
    • 2006.07b
    • /
    • pp.799-800
    • /
    • 2006
  • 외전형 모터는 내전형 모터에 비해 소형화 및 경량화 시킬 수 있는 특징을 가진다. 그러나 회전자와 고정자간의 공극사이에 이심률이 있을 때, 불균형 모멘트로 인한 토크 리플이 내전형보다 더 크게 일어나는 단점이 있다. 이전의 연구들은 회전자 슬롯 형상의 변화에 따른 모터의 변화를 유한요소해석법을 통해 알아보았다. 우리는 이러한 유한요소해석법을 통한 시뮬레이션을 통해 외전형 모터에서 이심률이 발생 및 증가함에 따라 나타나는 토크 리플을 줄일 수 있는 최적화된 슬롯형태를 찾아보았다.

  • PDF

Inquiry of Quadratic Curves According to Definition on Taxicab Geometry (택시기하에서 이차곡선의 정의 방법에 따른 그래프의 개형 탐구)

  • Heo, Nam Gu
    • Communications of Mathematical Education
    • /
    • v.31 no.2
    • /
    • pp.103-121
    • /
    • 2017
  • Taxicab geometry was a typical non-Euclid geometry for mathematically gifted. Most educational material related quadratic curves on taxicab geometry for mathematically gifted served them to inquire the graph of the curves defined by focis and constant. In this study, we provide a shape of quadratic curves on taxicab geometry by applying three definitions(geometric algebraic definition, eccentricity definition, conic section definition).

5.8GHz DSRC 시험 기술

  • 이심석
    • TTA Journal
    • /
    • s.90
    • /
    • pp.138-142
    • /
    • 2003
  • TTA에서 제공하고 있는 5.8GHz DSRC 장비에 대한 TTA Verified Conformance 시험은 올 11월 본격적인 시험$\cdot$인증 서비스를 시작하였으며, 본 글을 통해 서두에 DSRC 기술동향을 정리하여 그 흐름을 간략히 파악하고, 시험 동향을 살펴 기술검증의 필요성을 인식하며, 실제 적용사례를 제시함으로써 그 내용을 확인해보고자 한다.

  • PDF

Localization of Jet Engine Position from HRRP-JEM Images of Aircraft Targets Using Eccentricity of Complex-Valued Signals (항공기 표적의 HRRP-JEM 영상에서 복소 신호의 이심률을 이용한 제트 엔진 위치 추정)

  • Park, Ji-Hoon;Yang, Woo-Yong;Bae, Jun-Woo;Kang, Seong-Cheol;Myung, Noh-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.24 no.12
    • /
    • pp.1173-1180
    • /
    • 2013
  • High Resolution Range Profile-Jet Engine Modulation imagery first introduced in 2005 carries out radar target recognition by localizing the position of the jet engine installed on the aircraft target. This paper presents a new approach for estimating the jet engine position in the HRRP-JEM image based on the eccentricity of a complex signal. It can effectively evaluate the contribution of the JEM component to the radar received signal in a range bin of the HRRP-JEM image. Therefore, the localization is expected to be performed more quantitatively and reliably by pinpointing the range bin corresponding to the jet engine position where the JEM contribution is maximized. The simulation results of realistic aircraft models validated the effectiveness of the proposed concept.

Comparing Directional Parameters of Very Fast Halo CMEs (코로나질량방출의 방향지시 매개인수 비교)

  • Rho, Su-Lyun;Chang, Heon-Young
    • Journal of Astronomy and Space Sciences
    • /
    • v.25 no.4
    • /
    • pp.383-394
    • /
    • 2008
  • We examine geoeffective directional parameters of coronal mass ejections (CMEs). We select 30 front-side halo CMEs from SOHO LASCO CMEs whose speed is larger than 1000km/s and longitude is less than ${\pm}30^{\circ}$. These are thought to be the most plausible candidate of geoeffective CMEs. We examine the relation between CMEs directional parameters (Earthward direction, eccentricity, ${\Delta}$ distance and central angle parameter) and the minimum value of the Dst index. We have found that the Earthward direction parameter has a good correlation with the Dst index, the eccentricity parameter has a much better correlation with the Dst index. The bo distance and central angle parameter has a poor correlation with the Dst index. It's, however, well correlated with the Dst index in very strong geomagnetic storms. Most of CMEs causing very strong storms (Dst ${\leq}$-200nT) are found to have large Earthward direction parameter $({\geq}0.6)$, small eccentricity, bo distance and central angle parameters $(E{\leq}0.4,\;{\Delta}X\;and\;sin\;{\theta}{\leq}0.2)$. These directional parameters are very important parameters that control the geoeffectiveness of very fast front-side halo CMEs.