• 제목/요약/키워드: axis symmetry

검색결과 201건 처리시간 0.021초

1축 날개 조종형 고속회전 유도탄의 조정 특성 해석 (Analysis of control characteristics for high speed rolling guided missile with one axis steering fin)

  • 진정석;이재혁
    • 제어로봇시스템학회논문지
    • /
    • 제2권2호
    • /
    • pp.102-107
    • /
    • 1996
  • It is difficult to analyze the high speed rolling missile with the generally used missile body fixed coordinates. In this study, we formulate the dynamic equations of the high speed rolling missile with the principal axis of inertia, and make the analytical model of one axis steering missile using pitch/yaw symmetry and complex summation method. With this model we analyze the control characteristics and propose the design considerations of high speed rolling missile with one axis control fin using PNG law in conjuntion with a seeker signal.

  • PDF

이미지 데이터베이스에서 객체의 타원형 부분의 대칭특성에 기반을 둔 부분객체인식방법 (Partial Object Recognition based on Ellipse of Objects using Symmetry in Image Databases)

  • 조준서
    • 정보처리학회논문지B
    • /
    • 제15B권2호
    • /
    • pp.81-86
    • /
    • 2008
  • 이 논문에서 겹쳐지고 잘린 이미지내의 타원형 객체들 가운데 부분적으로 겹쳐져 보이지 않는 외형과 객체 내 영역을 재구성하고 계산하기 위한 방법을 제안한다. 대칭 속성을 이용하여 부분적으로 겹쳐져 보이지 않는 객체를 인식하기 위해서 객체내의 부분인식에 기반을 둔 방법이다. 이 방법은 객체 내에서 대칭축을 이용하여 영역 복사를 통한 보이지 않는 영역을 복원하는 간결한 방법을 제시한다. 이 방법은 통계적 예측보다 대칭 기반의 객체 복원에 의존하기 때문에 부분적으로 겹쳐져 보이지 않는 부분에 대해서 측정된 변수를 가지고 분류 트리를 이용하여 객체 인식를 수행한다. 이는 비록 객체의 자세에는 한계를 가지고 있지만 크기 변경이나 회전, 시각의 변화에서 부분적으로 가려진 객체를 인식하는데 뛰어난 것으로 나타났다.

대칭특성을 이용한 타원형 객체의 외형기반 부분인식에 관한 연구 (Contour-Based Partial Object Recognition Of Elliptical Objects Using Symmetry)

  • 조준서
    • 정보처리학회논문지B
    • /
    • 제13B권2호
    • /
    • pp.115-120
    • /
    • 2006
  • 이 논문에서 겹쳐지고 잘린 이미지내의 타원형 객체들 가운데 부분적으로 겹쳐져 보이지 않는 외형과 영역을 재구성하고 계산하기 위한 방법을 제안한다. 대칭적인 속성에 기반을 두고, 불완전한 객체 인식을 위해 타원형 객체의 윤곽에 기반을 둔 방법이다. 이 방법은 한 객체 안에서 대칭 축을 이용하는 영역 복사를 통한 겹쳐져 보이지 않는 영역을 재구성하는 간결한 기교를 제공한다. 부분적으로 겹쳐져 보이지 않는 영역에 대한 측정된 변수에 기반을 두고, 분류 트리의 객체 인지를 수행하는데, 이 방법은 통계 수치보다 대칭에 기반을 둔 객체 재구성에 의존하기 때문이다. 이는 크기 변경과, 객체의 자세, 회전, 등에서 비록 객체 자세에는 한계를 가지고 있지만 부분적으로 겹쳐져 보이지 않는 객체의 인지에서 탁월하다.

음차자이로의 동적특성 연구 (Dynamic Analysis of Toning-fork Gyroscope)

  • 곽문규;송명호
    • 한국소음진동공학회논문집
    • /
    • 제13권2호
    • /
    • pp.92-98
    • /
    • 2003
  • A rate gyroscope has been used popularly to measure the angular motion of a given vehicle using a symmetric rotor spinning rapidly about its symmetry axis. Since the rapid rotation is required in this type of gyroscope, the motor has been used to make the rotor spin, so that it results in a heavy configuration. The toning-fork gyroscope has been developed to avoid this problem, which utilizes a Coriolis coupling term and vibration about one axis. Due to the Coriolis effect, the vibration of one axis is transferred to other axis when the angular motion along the vibrating axis is given to the system. The concept of a tuning-fork gyroscope was recently realized using MEMS techniques. However, the dynamic characteristics of the tuning-fork gyroscope has not been discussed in detail. In this study. we derived the equations of motion for the tuning-fork type gyroscope using the energy approach and investigated the dynamic characteristics by means of numerical analysis.

음차자이로의 동적특성 연구 (Dynamic Analysis of Tuning-Fork Gyroscope)

  • 곽문규;한상보
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2002년도 춘계학술대회논문집
    • /
    • pp.247-252
    • /
    • 2002
  • A rate gyroscope has been used popularly to measure the angular motion of a given vehicle using a symmetric rotor spinning rapidly about its symmetry axis. Since the rapid rotation is required in this type of gyroscope, the motor has been used to make the rotor spin, so that it results in a heavy configuration. The tuning-fork gyroscope has been developed to avoid this problem, which utilizes a coriolis coupling term and vibration about one axis. Because of the coriolis effect, the vibration of one axis is transferred to other axis when the angular motion along the vibrating axis is given to the system. The concept of a tuning-fork gyroscope was recently realized using MEMS techniques. However, the dynamic characteristics of the tuning-fork gyroscope has not been discussed in detail. In this study, we derived the equations of motion for the tuning-fork type gyroscope using the energy approach and investigated the dynamic characteristics by means of numerical analysis.

  • PDF

Axis-Slope-Rotatable Designs for Experiments With Mixture

  • Park, Sung H.;Kim, Joo H.
    • Journal of the Korean Statistical Society
    • /
    • 제11권1호
    • /
    • pp.36-44
    • /
    • 1982
  • A new design concept, called axis-slope-rotatability, is presented for the design of experiments with mixtures. This is an analogue of the Box-Hunter (1957) rotatability for second order response surface designs. By choice of design, it is possible to make the variance of the estimated slopes along the component axes constant for all axial points equidistant from the center point of the factor space. This property is called axis-slope-rotatability for mixture experiments. When the Scheffe's second degree polynomial is used, it is shown that some symmetry conditions are sufficient for axis-slope-rotatability. Several designs having this property are illustrated.

  • PDF

$Bi_2Sr_2CaCu_2O_{8+\delta}$ 고온초전도체의 d-파 대칭성 증거로서의 $Pb/Bi_2Sr_2CaCu_2O_{8+\delta}$접합 투과전도특성 (Tunneling Characteristics in $Pb/Bi_2Sr_2CaCu_2O_{8+\delta}$ Junctions as an Evidence for a d-wave Order Parameter Symmetry in $Bi_2Sr_2CaCu_2O_{8+\delta}$ Superconductors)

  • Chang, Hyun-Sik;Lee, Hu-Jong
    • Progress in Superconductivity
    • /
    • 제2권2호
    • /
    • pp.65-70
    • /
    • 2001
  • $Pb/Bi_2Sr_2CaCu_2O_{8+\delta}$-single-crystal junctions with the tunneling direction along the c axis of the crystal were fabricated to obtain an s-wave-superconductor/d-wave-superconductor Josephson junctions. The tunneling R (T) curves and current-voltage characteristics show distinct features which can be explained only under the assumption that the order parameter of high-$T_c/Bi_2Sr_2CaCu_2O_{8+{\delta}}$ superconductors has a pure d-wave symmetry, which is in contrast to the case of $YBa_2Cu_3O_{7+{\delta$}}$erconductors where a minor s-wave component is also present..

  • PDF

횡 방향으로 회전하는 구 주위의 유동특성 (Laminar Flow past a Sphere Rotating in the Transverse Direction)

  • 김동주;최해천
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2002년도 학술대회지
    • /
    • pp.83-86
    • /
    • 2002
  • Numerical simulations are conducted for laminar flow past a sphere rotating In the transverse direction, in order to investigate the effect of the rotation on the characteristics of flow over a sphere. The Reynolds numbers considered are Re=100, 250 and 300 based on the free-stream velocity and the sphere diameter, and the rotational speeds are in the range of $0{\leq}{\omega}{\leq}1$, where ${\omega}^{\ast}$ is the maximum velocity on the sphere surface normalized by the free-stream velocity. At ${\omega}^{\ast}=0$ (without rotation), the flow past the sphere experiences steady axisymmeoy, steady planar-symmetry and unsteady planar-symmetry, respectively, at Re=100, 250 and 300. However, with rotation, the flow becomes planar-symmetric for all the cases investigated and the symmetry plane is orthogonal to the axis of the rotation. The flow is also steady or unsteady depending on both the Reynolds number and the rotational speed, and the vortical structures behind the sphere are significantly modified by the rotation. For example, at Re=300, hairpin vortices completely disappear in the wake at ${\omega}^{\ast}=0.4\;and\;0.6$, and at ${\omega}^{\ast}=1$ vortical structures of a high frequency are newly generated due to the shear layer instability. It is also shown that with increasing rotational speed, the time-averaged drag and lift coefficients increase monotonically.

  • PDF

Hinge Axis Point에 관한 연구 (A Study of the Hinge Axis Point)

  • 정금태
    • 대한치과보철학회지
    • /
    • 제22권1호
    • /
    • pp.72-78
    • /
    • 1984
  • The notion that the axis of the shaft of the articulator must coincide the patient's mandibular transverse axis tells us the importance of locating the axis precisely. When using kinematic axis to transfer a cast to an articulator, the anatomic asymmetry of the contralateral points will result in certain distortion when the axis transferred to an articulator where the mechanical axis produces symmetry. In this study, after locating the true hinge axis point with Denar hinge axis locator, the discrepancies between true hinge axis point and arbitrary hinge axis point that was 13mm anterior from the posterior margin of center of trangus to the outer canthus of eye were measured. And the discrepancies between left and right true hinge axis point in the superoinferior and anteroposterior directions were measured. For this study, 20 dental students who have no missing teeth and no difficulties of mandibular movement were selected. Upper and lower cast of subjects were mounted on Denar Mark II articulator uisng Denar Slidematic face-bow and centric relation record for the measurement of discrepancies between left and right true hinge axis points. The results obtained as follows. 1. The mean distance from the arbitrary hinge axis point to the true hinge axis point was as follows. Right: horizontal distance; 1.99mm, vertical distance; 2.12mm, linear distance; 3.36 mm. Left: horizontal distance; 1.39mm, vertical distance; 2.06mm, linear distance; 2.09mm. Total: horizontal distance; 1.69mm, vertical distance; 2.09mm linear distance; 3.06 mm. 2. The 87.5% of true hinge axis points were within 5mm of the arbitrary hinge axis point. 3. The mean discrepancies between the right and left hinge axis point were 2.92mm in superoinferior direction and 4.74mm in anteroposterior direction. 4. When transferring the axis to the articulator, anatomic asymmetry between right: and left axis point produces in dislocation of cast on the articulator, and undesirable shift in esthetic tooth position will be resulted.

  • PDF

3축 가속도 센서를 이용한 보행 불균형 평가 시스템에 관한 연구 (A Study on Gait Imbalance Estimation System using 3-axis Accelerometer)

  • 최항적;박용덕;심현민;이상민
    • 재활복지공학회논문지
    • /
    • 제9권1호
    • /
    • pp.37-43
    • /
    • 2015
  • 본 논문에서는 3축 가속도 센서를 이용하여 보행 불균형을 진단하는 효율적 시스템을 제안한다. 제안된 하드웨어 시스템은 주로 보행시 발목 세 방향의 가속도를 무선으로 측정할 수 있는 3축 가속도 센서와 데이터 전송을 위한 임베디드 시스템으로 구성되어 있다. 획득된 데이터를 정규화 처리한 후, ROCC (ratio of correlation coefficient)를 이용하여 정상적인 보행의 대칭성과 비정상적인 보행의 대칭성을 비교 분석하였다. 건강한 성인 10명을 대상으로 실험을 실시하였고 개인당 총 5회 반복 실험을 하였다. 비정상 보행을 만들기 위해 한쪽 발의 굽의 높이를 변화시켰다. 결과를 보면 보행 불균형이 커질수록 ROCC의 값이 점차 기준에서 멀어지는 것을 알 수 있었으며 제안된 시스템이 보행 불균형 평가에 사용가능한 것이 확인되었다.

  • PDF