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[Keyword] dynamic simulation(4hit)

1-4hit
  • Analysis and Optimization for the Operating Mechanism of Air Circuit Breaker

    Degui CHEN  Liang JI  Yunfeng WANG  Yingyi LIU  

     
    PAPER-Contactors & Circuit Breakers

      Vol:
    E91-C No:8
      Page(s):
    1280-1285

    This paper simulates the dynamic behavior of the operating mechanism of ACB, and analyzes factors influencing the mechanism's operating time. First, it builds a dynamic model for the mechanism with virtual prototype technology. Experiment validation is carried out to prove the correctness of the model. Based on this model, it puts emphasis on analyzing the influence of electro-dynamic repulsion force on the operating time of the mechanism. Simulation and experimental results show that after adding electric repulsion force to the model, the operating time is shortened about 1.1 ms. Besides the repulsion force, other influencing factors including the stiffness of opening spring, locations of every key axis, mass and centroidal coordinates of every mechanical part are analyzed as well. Finally, it makes an optimum design for the mechanism. After optimization, the velocity of operating mechanism is improved about 6.7%.

  • Human Spine Posture Estimation from 2D Frontal and Lateral Views Using 3D Physically Accurate Spine Model

    Daisuke FURUKAWA  Kensaku MORI  Takayuki KITASAKA  Yasuhito SUENAGA  Kenji MASE  Tomoichi TAKAHASHI  

     
    PAPER-ME and Human Body

      Vol:
    E87-D No:1
      Page(s):
    146-154

    This paper proposes the design of a physically accurate spine model and its application to estimate three dimensional spine posture from the frontal and lateral views of a human body taken by two conventional video cameras. The accurate spine model proposed here is composed of rigid body parts approximating vertebral bodies and elastic body parts representing intervertebral disks. In the estimation process, we obtain neck and waist positions by fitting the Connected Vertebra Spheres Model to frontal and lateral silhouette images. Then the virtual forces acting on the top and the bottom vertebrae of the accurate spine model are computed based on the obtained neck and waist positions. The accurate model is deformed by the virtual forces, the gravitational force, and the forces of repulsion. The model thus deformed is regarded as the current posture. According to the preliminary experiments based on one real MR image data set of only one subject person, we confirmed that our proposed deformation method estimates the positions of the vertebrae within positional shifts of 3.2 6.8 mm. 3D posture of the spine could be estimated reasonably by applying the estimation method to actual human images taken by video cameras.

  • Dynamic Simulation of the Left Coronary Circulation Using an Electronic Circuit Model for Coronary Vessel

    Tahseen EJAZ  Tadashi TAKEMAE  Yukio KOSUGI  Kazuhiro MATSUI  Shinichi OKUBO  Minoru HONGO  

     
    PAPER-Medical Engineering

      Vol:
    E83-D No:9
      Page(s):
    1805-1813

    An electronic model of the coronary vessel consisting of resistor, capacitor and Field Effect Transistor (FET) is proposed in order to perform a dynamic simulation of the left coronary circulation and to clarify its mechanisms. Based on this model, an equivalent circuit of the coronary circulation is constructed that is divided into subepicardial and subendocardial layers and consists of segments of artery, arteriole, capillary, venule and vein for both the layers. In this simulation, the observed flow waveform of the left main artery showed dominance of flow in diastole as compared to that in systole. In epicardium, inverse venous flow was observed in early systole. These simulated waveforms are similar to those in real left coronary circulation observed by physiological and clinical researchers. Among all the segments of intramyocardium, only the venules were found to possess a time-varying resistance characteristics. From the results of this study, it is considered that the combination of resistance and capacitance of the vessel acts as an integrator and a differentiator for blood pressure and intramyocardial pressure, respectively and that the effects of integration of blood pressure and differentiation of intramyocardial pressure play a very important role in determining the factors influencing the left coronary circulation.

  • Dynamic Simulation of Multiple Trapping Processes and Anomalous Frequency Dependence in GaAs MESFETs

    Shirun HO  Masaki OOHIRA  Osamu KAGAYA  Aya MORIYOSHI  Hiroshi MIZUTA  Ken YAMAGUCHI  

     
    PAPER-Device Simulation

      Vol:
    E77-C No:2
      Page(s):
    187-193

    A unified model for frequency-dependent characteristics of transconductance and output resistance is presented that incorporates the dynamics of quasi-Fermi levels. Using this model, multiple-frequency dispersion and pulse-narrowing phenomena in GaAs MESFETs are demonstrated based on the drift-diffusion transport theory and a Schockley-Read-Hall-type deep trap model, where rate equations for multiple trapping processes are analyzed self-consistently. It is shown that the complex frequency dependence is due to both spatial and temporal effects of multiple traps.