IEICE Electronics Express
Online ISSN : 1349-2543
ISSN-L : 1349-2543
Volume 5 , Issue 6
Showing 1-5 articles out of 5 articles from the selected issue
LETTER
  • Masahiro Hayashitani, Teruo Kasahara, Daisuke Ishii, Yutaka Arakawa, S ...
    2008 Volume 5 Issue 6 Pages 181-186
    Published: March 25, 2008
    Released: March 25, 2008
    JOURNALS FREE ACCESS
    We have developed the high-speed PLZT ((Pb, La)(Zr, Ti) O3) optical content distribution system having slot-switch and GMPLS controller in the 1X8 distribution switch. The switching speed of our developed system is less than 10 nsec and the world fastest switching time in the optical switch with more than 8 outputs. The system can switch transparent time slot whose size can range from 10 nsec to 1 sec. Each slot is reserved very quickly by an extended Resource reSerVation Protocol (RSVP) message that is now being standardized for the GMPLS control plane. According to calculations, the proposed system can handle more than 500 users with minimum receiving power of -18dBm, which is about an 8 fold improvement over Passive Optical Network (PON). We consider that the system well supports content distribution in the access network.
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  • D. Gharavian, S. M. Ahadi
    2008 Volume 5 Issue 6 Pages 187-191
    Published: March 25, 2008
    Released: March 25, 2008
    JOURNALS FREE ACCESS
    The use of emotion-initiated gestures in human speech communication results in the improvement of speech understanding. However, this is a source of difficulty for automatic speech recognizers. In this paper, using the orderly changes found in the second formant, due to stress, a warping function is introduced that can be applied to the mel frequency scale during the calculation of MFCC parameters. We show that this approach leads to improvements in the stressed speech recognition results. Furthermore, using the second formant frequency as an extra element of the feature vector leads to further improvements in the speech recognizer performance.
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  • Hyejeong Jeon, Seungil Kim, Lag-Yong Kim, Hee-Youn Lee, Hyunsoo Yoon
    2008 Volume 5 Issue 6 Pages 192-197
    Published: March 25, 2008
    Released: March 25, 2008
    JOURNALS FREE ACCESS
    In this paper, we propose a method of measuring the reliability of direction-of-arrival (DOA) estimation results. One idea for the reliability measure arises from a waterbed effect in DOA estimation. The reliability measure can be obtained from the difference between the maximum and minimum point of cross-correlation. If the calculated reliability measure has a lower value than a predefined threshold, the estimated DOA is regarded as a wrong result and subsequently discarded. Some experiments show that the proposed method can reject perturbed results of the estimated DOA.
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  • Tsuyoshi Funaki, Tsunenobu Kimoto, Takashi Hikihara
    2008 Volume 5 Issue 6 Pages 198-203
    Published: March 25, 2008
    Released: March 25, 2008
    JOURNALS FREE ACCESS
    This paper experimentally studies the temperature dependencies of current-voltage (I-V) and capacitance-voltage (C-V) characteristics of SiC power devices, and discusses the relationships between physical phenomena and the measured characteristics in SiC. Two SiC Schottky barrier diodes (SBD) with different specifications were studied for temperatures ranging from 25 to 450°C. Their I-V characteristics show that SBDs indeed function as rectifiers at extremely high temperatures, but forward conduction and reverse blocking performance significantly deteriorates when the temperature exceeds 200°C. C-V characteristics show diffusion potential reduction with temperature, and p-n junction characteristics were found for the junction barrier Schottky structure.
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  • Tetsuya Hirose, Tetsuya Asai, Yoshihito Amemiya
    2008 Volume 5 Issue 6 Pages 204-210
    Published: March 25, 2008
    Released: March 25, 2008
    JOURNALS FREE ACCESS
    This paper proposes a low-current reference circuit for power-aware LSI applications. The circuit consists of two current generation subcircuits which are based on β-multiplier circuit, one with a positive and the other with a negative temperature coefficient. The variation of the reference current in a sample circuit designed to produce a current of 230nA can be kept very small within ±1.3% in a wide temperature range of -20 to 100°C.
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