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[Author] Takayuki NAKATA(3hit)

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  • A Study on Site Diversity Techniques Related to Rain Area Motion Using Ku-Band Satellite Signals

    Yasuyuki MAEKAWA  Takayuki NAKATANI  Yoshiaki SHIBAGAKI  Takeshi HATSUDA  

     
    PAPER-Propagation

      Vol:
    E91-B No:6
      Page(s):
    1812-1818

    Directions and speeds of the motion of rain areas are estimated for each type of rain fronts, using time differences detected in the rain attenuation of the Ku-band satellite radio wave signals that have been measured at Osaka Electro-Communication University (OECU) in Neyagawa, Osaka, Research Institute of Sustainable Humanosphere (RISH) in Uji, Kyoto, and MU Observatory (MU) of Kyoto University in Shigaraki, Shiga, for the past five years since September 2002. These directions and speeds are shown to agree well with those directly obtained from the motion of rain fronts in the weather charts published by Japan Meteorological Agency. The rain area motion is found to have characteristic directions according to each rain type, such as cold and warm fronts or typhoon. A numerical estimate of the effects of site diversity techniques indicates that between two sites among the three locations (OECU, RISH, MU) separated by 20-50 km, the joint cumulative time percentages of rain attenuation become lower as the two sites are aligned along the directions of rain area motion. In such a case, compared with the ITU-R recommendations, the distance required between the two sites may be, on an average, reduced down to about 60-70% of the conventional predictions.

  • Dynamic Image Adjustment Method and Evaluation for Glassless 3D Viewing Systems

    Takayuki NAKATA  Isao NISHIHARA  

     
    PAPER-Image Processing and Video Processing

      Pubricized:
    2020/08/24
      Vol:
    E103-D No:11
      Page(s):
    2351-2361

    In this paper, we propose an accurate calibration method for glassless stereoscopic systems. The method uses a lenticular lens on a general display. Glassless stereoscopic displays are currently used in many fields; however, accurately adjusting their physical display position is difficult because an accuracy of several microns or one hundredth of a degree is required, particularly given their larger display area. The proposed method enables a dynamic adjustment of the positions of images on the display to match various physical conditions in three-dimensional (3D) displays. In particular, compared with existing approaches, this avoids degradation of the image quality due to the image location on the screen while improving the image quality by local mapping. Moreover, it is shown to decrease the calibration time by performing simultaneous processing for each local area. As a result of the calibration, the offset jitter representing the crosstalk reduces from 14.946 to 8.645 mm. It is shown that high-quality 3D videos can be generated. Finally, we construct a stereoscopic viewing system using a high-resolution display and lenticular lens and produce high-quality 3D images with automatic calibration.

  • Internet Access System with GMPLS Architecture Configured on Wavelength Assignment Photonic Switching System

    Tadahiko YASUI  Takuya KAMINOGOU  Takayuki NAKATA  Hironari MATSUDA  

     
    PAPER-Fiber-Optic Transmission for Communications

      Vol:
    E90-B No:4
      Page(s):
    836-844

    We have successfully applied Generalized Multiprotocol Label Switching (GMPLS) architecture to the Wavelength Assignment Photonic Switching System (WAPS) to create an internet access system that can provide, between terminals, not only conventional best-effort type of IP packet forwarding, but also high-speed and Quality of Service (QoS)-guaranteed IP forwarding. In this paper the system architecture, system specifications, and system hardware/software implementations are described.