• Title/Summary/Keyword: virtual rotation

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A Human Sensibility Ergonomics Method for Vehicle Driving Simulator and Verbal Expressions Collected (자동차 주행 시뮬레이터의 운동감 재현 및 감성평가를 위한 감성어휘의 수집)

  • Jeong, Yeong-Hun;Eom, Seong-Suk;Son, Gwon;Choe, Gyeong-Hyeon
    • Journal of the Ergonomics Society of Korea
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    • v.19 no.2
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    • pp.1-14
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    • 2000
  • Driving simulators have been developed for evaluating users' reaction to various driving situations. Dynamic simulators have, however, limitations of the motion feedback in space. Therefore, this paper presents a driving simulator and suggests a human sensibility ergonomics (kansei engineering) method to be used in improving sense of motion through a vehicle simulator. Human sensibility ergonomics(kansei engineering) is defined as translating technology of the customer' feeling about a new product into design elements. Constituents of the simulator were defined and the virtual world was generated by the object modeling technique. Senses perceived were classified into feelings of velocity, acceleration, rotation, and vibration based on the human sensibility associated with driving. And the most frequent verbal expressions were collected from 17 male subjects to define complex human sensibility.

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Spatial Free Vibration and Stability Analysis of Thin-Walled Arches with Variable Curvature (곡률이 변하는 박벽 아치의 3차원 자유진동 및 좌굴해석)

  • 서광진;민병철;김문영
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.04a
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    • pp.169-176
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    • 1999
  • An improved formulation for spatial stability md free vibration of thin-walled curved beams with variable curvature and non-symmetric cross sections are presented based on the displacement field considering the second order terms of finite semitangential rotations. By introducing Vlasov's assumptions, the total potential energy is derived from the principle of linearized virtual work for a continuum. In this formulation, all displacement parameters and the warping function are defined at the centroid axis so that the coupled terms of bending and torsion are added to the elastic strain energy. Also, the potential energy due to initial stress resultants is consistently derived corresponding to the semitangential rotation and moment. The cubic Hermitian polynomials are utilized as shape functions for development of the curved thin-walled beam element having eight degrees of freedom. In order to illustrate the accuracy and practical usefulness of this study, . numerical solutions for free vibration of arches are presented and compared with resells of other researchers and solutions analyzed by the ABAQUS's shell element.

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An Euler Parameter Updating Method for Multibody Kinematics and Dynamics (다물체의 기구해석 및 동적거동해석을 위한 오일러 매개변수의 교정방법)

  • 김성주;배대성;최창곤;양성모
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.4
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    • pp.9-17
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    • 1996
  • This paper develops a sequential updating method of the Euler parameter generalized coordinates for the machine kinematics and dynamics, The Newton's method is slightly modified so as to utilize the Jacobian matrix with respect to the virtual rotation instead of this with repect to the Euler parameters. An intermediate variable is introduced and the modified Newton's method solves for the variable first. Relational equation of the intermediate variable is then solved for the Euler parameters. The solution process is carried out efficiently by symoblic inversion of the relational equation of the intermediate variable and the iteration equation of the Euler parameter normalization constraint. The proposed method is applied to a kinematic and dynamic analysis with the Generalized Coordinate Partitioning method. Covergence analysis is performed to guarantee the local convergence of the proposed method. To demonstrate the validity and practicalism of the proposed method, kinematic analysis of a motion base system and dynamic analysis of a vehicle are carried out.

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Analytical Study on Inner Flow and Structural Stiffness in Vane Type of Vacuum Pump (베인형 진공펌프의 내부유동과 구조 강성에 관한 해석적 연구)

  • Son, Taekwan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.2
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    • pp.201-206
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    • 2017
  • In the study, the inner flow characteristics were analyzed by modifying the inner design parameter of the vane-type vacuum pump. The effect of pressure generated by the inner flow of pump on the rotor and vane was analyzed. The design parameter was analyzed using the angle variation of tilting and rotation of the vane. MRF was used for the analysis conducted using a virtual condition where the rotor and vane are rotated. The pressure gained from the load of the rotor and vane in the flow analysis is used for the structure analysis. Based on the results, the effect of variable vane design was revealed in structural strength. The effect of centrifugal and friction force generated during pump operation on structural strength was also analyzed.

Spatial Stability of Monosymmetric Thin-walled Circular Arch (일축대칭 단면을 갖는 박벽 원형아치의 면외좌굴해석)

  • 김문영;민병철
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.449-456
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    • 1998
  • A consistent finite element formation and analytic solutions are presented for spatial stability of thin-walled circular arch. The total potential energy is derived by applying the principle of linearized virtual work and including second order terms of finite semitangential rotations. As a result the energy functional corresponding to the semitangential rotation is obtained, in which the elastic strain energy terms are considered restrained warping effects. We have obtained analytic solution for the lateral buckling of monosymmetric thin-walled curved beam subjected to pure bending or uniform compression and it's boundary conditions are simply supported. For finite element analysis, the two node cubic Hermitian polynomials are utilized as shape Auctions. In order to illustrate the accuracy of this study, parameter studies for lateral buckling problems of circular arch are presented and compared with available solutions and numerical results analyzed by the FEM using straight beam element.

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Estimation of Trifocal Tensor with Corresponding Mesh of Two Frontal Images

  • Tran Duy Dung;Jun Byung Hwan
    • Proceedings of the IEEK Conference
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    • summer
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    • pp.133-136
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    • 2004
  • We are going to procedure various view from two frontal image using trifocal tensor. We found that warping is effective to produce synthesized poses of a face with the small number of mesh point of a given image in previous research[1]. For this research, fundamental matrix is important to calculate trifocal tensor. So, in this paper, we investigate two existing algorithms: Hartley's[2] and Kanatani's[3]. As an experimental result, Kenichi Kantani's algorithm has better performance of fundamental matrix than Harley's algorithm. Then we use the fundamental matrix of Kenichi Kantani's algorithm to calculate trifocal tensor. From trifocal tensor we calculate new trifocal tensor with rotation input and translation input and we use warping to produce new virtual views.

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Dealing with gravity on galactic scales

  • Trippe, Sascha
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.36.1-36.1
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    • 2013
  • I present a simple scheme for the treatment of gravitational interactions on galactic scales. In analogy with known mechanisms of quantum field theory, I assume ad hoc that gravitation is mediated by virtual exchange particles - gravitons - with very small but non-zero masses. The scheme predicts the asymptotic flattening of galactic rotation curves, the Tully-Fisher/Faber-Jackson relations, the mass discrepancy-acceleration relation of galaxies, and the surface brightness-acceleration relation of galaxies correctly; additional (dark) mass components are not required. The well-established empirical scaling laws of Modified Newtonian Dynamics follow naturally from the model. The scheme I present is not a consistent theory of gravitation; rather, it is a toy model providing a convenient scaling law that simplifies the description of gravity on galactic scales.

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A Dual-User Multiplexing Scheme Using Time Diversity over Frequency Nonselective SIMO Fading Channels (주파수 비선택적 SIMO 페이딩 채널에서 단일 송신 안테나 및 시간 다이버시티를 이용한 두 사용자의 동시 전송 기법)

  • Choi, Byoungjo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.2
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    • pp.127-142
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    • 2013
  • A dual-user multiplexing scheme for a pair of mobiles equipped with single antenna is proposed which incorporates time-delay diversity employing a rotation-based D-BLAST-like layered code. A low-dimension equivalent of the existing partial interference cancellation based group decoder is also proposed for the corresponding receiver. The BER performances of the proposed scheme and those of the ideal scheme are studied comparatively through Monte Carlo simulations.

A study on the nonlinear analysis of spatial frame structures with nonlinear rotational spring elements (비선형 회전 스프링 요소를 갖는 공간 프레임의 구조의 비선형 해석에 관한 연구)

  • 이병채;박문식
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.2
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    • pp.29-42
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    • 1990
  • Three dimensional frame structures with such nonlinearities as large displacements, medium rotations, plastic hinges and local defects are efficiently analyzed by introducing the nonlinear rotational spring. Formulations are based on the incremental updated Lagrangian descriptions and the virtual work principle, Axial displacement and twisted angle in beam elements are interpolated linearly, while bending displacements are approximated by the Hermite polynomials. The modified are length method is used as a solution method. The moment-angle of rotation relationship obtained analytically or experimentally can be easily incorporated into the solution procedure. Several examples tested show that the present method can be used efficiently in analyzing nonlinear frame structures with plastic hinges or local defect.

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Modeling and Dynamic Analysis of a Front Loaded Washing Machine with Ball Type Automatic Balancer (볼 자동균형장치를 채용한 드럼세탁기의 모델링 및 동적 거동 해석)

  • 이준영;조성오;김태식;박윤서
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.119-131
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    • 1997
  • Ball type automatic balancer is used to reduce the vibration caused by unbalance of rotor. In this study, A analytic modeling of a front loaded washing machine with ball type automatic balancer has been suggested theoretically and ADAMS has been used to analyze the dynamic characteristics of automatic balancer. It is found from simulation and experimental results that the automatic balancer suppress the steady state vibration of the washing machine effectively. The test results match well with the simulation results of ADAMS, thereby the dynamic model of ADAMS can be used as virtual prototype to predict the vibration characteristics which could be changed by the modification of design variable and can reduce the design cycle sharply. To maximize the balancing effect of automatic balancer, the friction between balls and race and the deviation between geometric center and rotation center of drum need to be minimized and the optimum design for the stiffness of flange shaft and the angular acceleration of drum should be achieved.

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