Journal of Signal Processing
Online ISSN : 1880-1013
Print ISSN : 1342-6230
Current issue
Journal of Signal Processing, Vol.23 (2019) No.1 (Editor-in-Chief: Keikichi Hirose, Editor: Tetsuya Shimamura, Honorary Editor-in-Chief: Takashi Yahagi)
Showing 1-4 articles out of 4 articles from the selected issue
  • Tomoya Hayakawa, Masakatsu Ogawa
    2019 Volume 23 Issue 1 Pages 1-8
    Published: January 25, 2019
    Released: January 25, 2019
    JOURNALS FREE ACCESS

    Waiting lines are an everyday occurrence in various places. In this paper, we propose a waiting line and waiting time estimation method based on crowd behavior characteristics. The crowd behavior characteristics in a waiting line concern the user actions, where users are either moving or stationary. The proposed method considers the following three types of user movement using the receive signal strength indicator (RSSI) and user action estimated by an acceleration sensor: the user movement of entering the waiting line, the user movement following the crowd behavior characteristic while lining up in the waiting line, and the user movement of leaving the waiting line. Using these movements, the proposed method estimates the waiting line and waiting time. Through experiments, we obtained 95.0% estimation accuracy in the waiting line estimation, so we could mostly distinguish people in a waiting line from those outside. In addition, we obtained a mean estimation error of 2.0 s in the waiting time estimation, so we could obtain the waiting time with high accuracy.

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  • Reona Gomi, Hidekazu Aizawa, Eri Sato-Shimokawara, Toru Yamaguchi
    2019 Volume 23 Issue 1 Pages 9-22
    Published: January 25, 2019
    Released: January 25, 2019
    JOURNALS FREE ACCESS

    The formation of human relationships is important to form communities. As a supporting system to strengthen the bonding among community members, we firstly tried to connect users by co-occurrence and mutual assistance matching to form relationships. Then, we brought them together. At the time of this experiment, users can easily carry on animated conversations if a common topic is suggested to them. In this study, we utilized a questionnaire to acquire user's personal characteristics for co-occurrence and mutual assistance matching. Next, we conducted a conversation experiment via Skype to investigate activation and inactivation during user's conversations by using speech dialogue and the LF/HF ratio calculated from user's heart rates. During the conversation experiment, matched users made conversations for 10 min on each common topic based on their interests suggested. The result showed that users could easily have animated conversations when a common topic was suggested to them. In addition, we investigated acoustic features, the overlap of utterances, and the number of utterances, backchannel feedbacks, and laughter.

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  • Souichiro Morita, Akinobu Murayama, Nanase Yumoto, Kouki Nakatsukasa, ...
    2019 Volume 23 Issue 1 Pages 23-34
    Published: January 25, 2019
    Released: January 25, 2019
    JOURNALS FREE ACCESS

    In order to improve channel sounding performance, this paper discusses channel sounders employing modified maximal length (M) sequences for acoustic communications in severe time and frequency selective environment, i.e., doubly selective environment. There still exist the following issues in the conventional channel sounders employing M sequences: 1) M sequences have side-lobe for their auto-correlations; 2) they output acoustic signals in undesired frequency band; 3) estimated channel impulse responses are time-varying due to sampling frequency deviation between Tx/Rx sides. This paper employs the modified M sequences, band pass filters in Tx/Rx sides and over-sampling signal processing employing interpolation for the items 1), 2) and 3), respectively. Next, computer simulation results and experimental results confirm that the proposed schemes improve channel sounding performance. Finally, this paper evaluates actual acoustic channel environments using the proposed channel sounders.

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  • Nobuo Nagai, Takashi Yahagi
    2019 Volume 23 Issue 1 Pages 35-40
    Published: January 25, 2019
    Released: January 25, 2019
    JOURNALS FREE ACCESS

    Circuit theory includes steady-state responses that are obtained using the Laplace transform; however, they are not included in classical physics. By applying the Laplace transform to the Dirac equation as a basic equation of quantum theory, we can examine the steady-state response in quantum theory and determine the spin 1/2 as a characteristic phenomenon in this theory.

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