IEICE Communications Express
Online ISSN : 2187-0136
ISSN-L : 2187-0136
10 巻 , 12 号
選択された号の論文の25件中1~25を表示しています
Special Cluster in Conjunction with IEICE General Conference 2021
Regular Section
  • Genki Isobe, Daisuke Katayama, Sora Aketani, Takahiro Koita
    原稿種別: LETTER
    専門分野: Network
    2021 年 10 巻 12 号 p. 991-996
    発行日: 2021/12/01
    公開日: 2021/12/01
    [早期公開] 公開日: 2021/09/08
    ジャーナル フリー

    Amazon EC2 provides Spot Instances that may change prices with time. To use them more efficiently, it is necessary to understand the Spot price fluctuations. This study evaluates the Spot price fluctuations with normalized values by On-Demand prices and Historical Volatilities (HVs). Then, using evaluation results, we classify the Instances into five groups. Each group has features of the Spot price fluctuations. We conclude that the groups that have a small fluctuation range are able to bid easily. Therefore, for the groups that have a large fluctuation range, we need more detailed evaluation standards.

  • Ryota Kawasaki, Akihiro Kajiwara
    原稿種別: LETTER
    専門分野: Sensing
    2021 年 10 巻 12 号 p. 997-1002
    発行日: 2021/12/01
    公開日: 2021/12/01
    [早期公開] 公開日: 2021/09/10
    ジャーナル フリー

    Blood pressure (BP) is one of the four main vital signs providing valuable medical information about the cardiovascular activity. In this paper, a new method for estimating systolic and diastolic BP in contact-free for comfort is proposed using a millimeter-wave (MMW) sensor. The MMW sensor is sensitive to small cardiac motion of 1mm or less included in chest surface motion because of the higher frequency and wider bandwidth available, thereby continuous systolic and diastolic BP per heartbeat would be able to be estimated from the time-domain features of unique cardiac motion waveform. Measurement was conducted with the MMW sensor system and the estimated systolic and diastolic BP are also compared with an intermittent BP monitor. As a result, the sensor system is found to estimate systolic and diastolic BP continuously.

  • Ryuta Sakamoto, Ryogo Kubo
    原稿種別: LETTER
    専門分野: Network
    2021 年 10 巻 12 号 p. 1003-1008
    発行日: 2021/12/01
    公開日: 2021/12/01
    [早期公開] 公開日: 2021/09/10
    ジャーナル フリー

    The quality of experience (QoE) is an index that evaluates the application-level quality of network services. In adaptive video streaming, stabilization of playback buffer level improves the QoE by avoiding video freezing. Although control-theoretic approaches for stabilizing the buffer level are effective to improve the QoE for a single user, they have not considered user preferences of the QoE or bandwidth allocation for multiple users. This study proposes a dynamic bandwidth allocation method that satisfies the QoE requirements of multiple users with different preferences. Simulation results show that the proposed method increases the number of satisfied users and QoE fairness for prioritized users at the expense of the average QoE for all users.

  • Ryosuke Koyanaka, Shunsuke Sato, Yaokun Hu, Takeshi Toda
    原稿種別: LETTER
    専門分野: Sensing
    2021 年 10 巻 12 号 p. 1009-1014
    発行日: 2021/12/01
    公開日: 2021/12/01
    [早期公開] 公開日: 2021/09/22
    ジャーナル フリー

    We have been considering applying discrete wavelet transform (DWT) to heart-rate estimation using 77GHz band FMCW radar. The detection accuracy and SNR were improved by using an elliptic High-pass filter (HPF) and a High-pass Chebyshev type II filter. The High-pass Chebyshev Type II filter has less ripple in the passband area, on the other the elliptic HPF has a steeper frequency response compared to the Chebyshev filter. Those filters were used in a pre-processing of DWT for the data acquired from the front and back to reduce respiratory signals and harmonics for comparison. In this letter, the detection accuracy and SNR estimated from the front and back were improved by using two types of filters in DWT pre-processing to decrease respiratory signals.

  • Mizuki Suga, Kota Ito, Takuto Arai, Yushi Shirato, Naoki Kita, Takeshi ...
    原稿種別: LETTER
    専門分野: Wireless Communication Technologies
    2021 年 10 巻 12 号 p. 1015-1020
    発行日: 2021/12/01
    公開日: 2021/12/01
    [早期公開] 公開日: 2021/09/24
    ジャーナル フリー

    Radio over fiber (RoF) technology, especially intermediate frequency over fiber (IFoF), is attracting much attention as one way to realize high frequency band systems. Such systems require beamforming to attain the desired link budget. Furthermore, highly accurate beamforming permits the adoption of space division multiplexing (SDM), with its greater system capacity. Since beamforming should be controlled by the central station to achieve simple base stations, we proposed a novel remote beamforming scheme with fixed wavelength allocation. This paper introduces experiments conducted on modulated signals to evaluate the characteristics of the scheme’s beamforming gain and signal to interference ratio (SIR).

  • Song-Ju Kim, Hiroyuki Yasuda, Ryoma Kitagawa, Mikio Hasegawa
    原稿種別: LETTER
    専門分野: Wireless Communication Technologies
    2021 年 10 巻 12 号 p. 1021-1025
    発行日: 2021/12/01
    公開日: 2021/12/01
    [早期公開] 公開日: 2021/10/01
    ジャーナル フリー

    We propose a simple channel-allocation method based on tug-of-war (TOW) dynamics, combined with the time scheduling based on nonlinear oscillator synchronization to efficiently use of the space (channel) and time resources in wireless communications. This study demonstrates that synchronization groups, where each node selects a different channel, are non-uniformly distributed in phase space such that every distance between groups is larger than the area of influence. New type of self-organized spatiotemporal patterns can be formed for resource allocation according to channel rewards.

  • Zhongda Liu, Takeshi Murakami, Satoshi Kawamura, Hitoaki Yoshida
    原稿種別: LETTER
    専門分野: Network System
    2021 年 10 巻 12 号 p. 1026-1031
    発行日: 2021/12/01
    公開日: 2021/12/01
    [早期公開] 公開日: 2021/10/05
    ジャーナル フリー

    With the proliferation of automotive electronic devices, electronic control units are increasingly used to share information within in-vehicle networks. This induces a range of security risks, such as information disclosure, spoofing, and tampering. In this paper, we propose a symmetric-key cipher. The method generates pseudo-random numbers using a chaotic and random neural network, and encrypts and decrypts frame messages of in-vehicle networks based on the symmetric key. We also propose a lightweight ID-based key sharing protocol. We evaluated the key sharing, encryption, and decryption in Controller Area Network.

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