• 제목/요약/키워드: Cartesian

검색결과 669건 처리시간 0.039초

TETRA 신호를 위한 800 MHz 대역 1W 급 Cartesian feedback 선형 전력 증폭기에 관한 연구 (A Study on 800 MHz 1W Cartesian Feedback Linearized Power Amplifier for TETRA Signals)

  • 오덕수;김지연;전상현;김종헌
    • 한국ITS학회 논문지
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    • 제7권4호
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    • pp.76-85
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    • 2008
  • 본 논문에서는 TETRA 단말기용 800 MHz 대역 1 W급 cartesian feedback 선형전력증폭기를 설계 및 제작하였다. 200 kHz 협대역을 갖는 TETRA 신호를 증폭 시, cartesian feedback 선형화기를 통해서 ${\pm}25$ kHz 오프셋 주파수에서 30 dBc 이상의 전력증폭기 선형성을 개선하였다. 선형화의 성능은 I/Q 신호간의 이득과 위상의 불일치 및 DC offset 성분에 의해서 영향을 받음을 알 수 있으며 이러한 문제를 보상 시 선형화를 극대화 할 수 있음을 알 수 있었다. Cartesian feedback 선형화기는 협대역 QAM 신호의 선형화 기술로 적합함을 확인하였으며 이를 이용하여 다른 변조방식을 갖는 신호들의 선형화방법으로도 적용 가능하다.

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로봇 매니퓰레이터의 직교공간 적응제어 방식 (A Cartesian Space Adaptive Control Scheme for Robot Manipulators)

  • 황석용;유준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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    • pp.397-400
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    • 1991
  • This paper presents a cartesian space decentralized adaptive controller design for the end effector of the robot manipulator to track the given desired trajectory in the cartesian coordinate. By the cartesian based control scheme, the task related high level motion command is directly executed without solving the complex inverse kinematic equations. The controller does not require the complex manipulator dynamic model, and hence it is computationally very efficient. Each degree of freedom of the end effector on the cartesian space is controlled by a PID feedback controller and a velocity acceleration feed forward conpensation part. Simulation results for a two-link direct drive manipulator conform that the present cartesian based decentralized scheme is feasible.

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직각좌표 공간에서 로봇 매니퓰레이터의 직선 궤적계획에 관한 연구 (A Study on Straight Line Trajectoties of Robot Mainpulator in Cartesian Space)

  • 한상완;홍석교
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1991년도 하계학술대회 논문집
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    • pp.763-766
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    • 1991
  • The moving of each axis in the robot manipulator can be represented with the motion of cartesian space. This paper shows the robot manipulator of the straight line trajectory planning algorithms in the cartesian space. The relation formulas between cartesian space and joint space are induced to accomplish a desired trajectory in the cartesian space and the velocity vector of sampling time in the cartesian space is transformed into the velocity vector of joint by the interpolation method. The error of trajectory in moving is removed by obtaining the real position for the present joint position and the desired distance is made by comparing the real position and the next position. Through the simple tests for suggested algorithms are confirmed the validity of algorithms.

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부분 시스템 해석을 위한 상대 직교 좌표를 이용한 다물체 동역학 공식 (Multibody Dynamics Formulation based on Relative Cartesian Coordinates for Subsystem Dynamic Analysis)

  • 김성수;송금정;허재영
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.899-904
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    • 2004
  • Multibody dynamics formulation has been developed based on relative cartesian coordinates for subsystem analysis. Relative cartesian coordinates are defined with respect to a reference body of a subsystem. Relative cartesian formulation inherits the same merits of absolute cartesian formulation, such as generality and easy implementation. Two methods have been applied. One is Largrange Multiplier Elimination method and the other is independent coordinate method. A 1/4 car simulation has been carried out to verify the formulations. Since both methods provide identical results, it proves the validity of the formulation.

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ACR 팬텀을 이용한 Cartesian Trajectory와 MultiVane Trajectory의 비교분석 : 영상강도 균질성과 저대조도 검체 검출률 test를 사용하여 (Comparative Analysis of Cartesian Trajectory and MultiVane Trajectory Using ACR Phantom in MRI : Using Image Intensity Uniformity Test and Low-contrast Object Detectability Test)

  • 남순권;최준호
    • 대한방사선기술학회지:방사선기술과학
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    • 제42권1호
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    • pp.39-46
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    • 2019
  • This study conducted a comparative analysis of differences between cartesian trajectory in a linear rectangular coordinate system and MultiVane trajectory in a nonlinear rectangular coordinate system axial T1 and axial T2 images using an American College of Radiology(ACR) phantom. The phantom was placed at the center of the head coil and the top-to-bottom and left-to-right levels were adjusted by using a level. The experiment was performed according to the Phantom Test Guidance provided by the ACR, and sagittal localizer images were obtained. As shown in Figure 2, slices # 1 and # 11 were scanned after placing them at the center of a $45^{\circ}$ wedge shape, and a total of 11 slices were obtained. According to the evaluation results, the image intensity uniformity(IIU) was 93.34% for the cartesian trajectory, and 93.19% for the MultiVane trajectory, both of which fall under the normal range in the axial T1 image. The IIU for the cartesian trajectory was 0.15% higher than that for the MultiVane trajectory. In axial T2, the IIU was 96.44% for the cartesian trajectory, and 95.97% for the MultiVane trajectory, which fall under the normal range. The IIU for the cartesian trajectory was by 0.47% higher than that for the MultiVane trajectory. As a result, the cartesian technique was superior to the MultiVane technique in terms of the high-contrast spatial resolution, image intensity uniformity, and low-contrast object detectability.

CONSTRUCTION OF CARTESIAN AUTHENTICATION CODES OVER UNTITRAY GEOMETRY

  • Xu, Wenyan;Gao, You
    • Journal of applied mathematics & informatics
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    • 제27권5_6호
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    • pp.1481-1488
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    • 2009
  • A construction of Cartesian authentication codes over unitary geometry is presented and its size parameters are computed. Assuming that the encoding rules are chosen according to a uniform probability distribution, the probabilities of success for different types of attacks are also computed.

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로보트 운동에 대한 공간 좌표 제어 (Cartesian Coordinate Control of Robot Motion)

  • 노영식;우광방
    • 대한전기학회논문지
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    • 제35권5호
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    • pp.177-184
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    • 1986
  • An effective cartesian coordinate model is presented to control a robot motion along a prescribed timebased hand trajectory in cartesian coordinates and to provide an adaptive feedback design approach utilizing self-tuning control methods without requiring a detailed mathematical description of the system dynamics. Assuming that each of the hybrid variable set of velocities and forces at the cartesian coordinate level is mutually independent, the dynamic model for the cartesian coordinate control is reduced to first-order SISO models for each degree of freedom of robot hand, including a term to represent all unmodeled effects, by which the number of parameters to be identified is minimized. The self-tuners are designde to minimize a chosen performance criterion, and the computed control forces are resolved into applied joint torques by the Jacobian matrix. The robustness of the model and controller is demonstrated by comparing with the other catesian coordinate controllers.

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The Basis Number of the Cartesian Product of a Path with a Circular Ladder, a Möbius Ladder and a Net

  • Alzoubi, Maref Y.;Jaradat, Mohammed M.M.
    • Kyungpook Mathematical Journal
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    • 제47권2호
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    • pp.165-714
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    • 2007
  • The basis number of a graph G is the least positive integer $k$ such that G has a $k$-fold basis. In this paper, we prove that the basis number of the cartesian product of a path with a circular ladder, a M$\ddot{o}$bius ladder and path with a net is exactly 3. This improves the upper bound of the basis number of these graphs for a general theorem on the cartesian product of graphs obtained by Ali and Marougi, see [2]. Also, by this general result, the cartesian product of a theta graph with a M$\ddot{o}$bius ladder is at most 5. But in section 3 we prove that it is at most 4.

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전자기 구동장치를 이용한 병렬형 6자유도 스테이지의 위치제어 (A Position Control for a Parallel Stage with 6 degrees of freedom Using Magnetic Actuators)

  • 이세한
    • 한국정밀공학회지
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    • 제22권7호
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    • pp.102-111
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    • 2005
  • In this paper, we address a position control for a parallel stage, which is levitated and driven by electric magnetic force. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal force. A dynamic equation of the stage system is derived based on Newton-Euler method and it's special Jacobian matrix describing a relation between the limited velocity and Cartesian velocity is done. There are proposed two control methods for positioning which are Cartesian space controller and Actuator space controller. The control performance of the Cartesian space controller is better than the Actuator space controller in task space trajectory while the Actuator space controller is simpler than the Cartesian space controller in controller realization.