IEICE ESS Fundamentals Review
Online ISSN : 1882-0875
ISSN-L : 1882-0875
Volume 14, Issue 3
Displaying 1-25 of 25 articles from this issue
Table of Contents
Review Papers
Proposed by RCC (Reliable Communication and Control)
  • Naoki HAYASHI, Naoyuki HARA
    2021 Volume 14 Issue 3 Pages 170-180
    Published: January 01, 2021
    Released on J-STAGE: January 01, 2021

    Wind power generation is attracting much attention as a clean power generation method with low greenhouse gas emissions and is being introduced in countries around the world. In general, wind power generation is operated by a wind farm that deploys a large number of wind turbines on a large scale. Such a large-scale wind farm can be modeled as a multiagent system that consists of wind turbines as subsystems. Recently, research on distributed optimization has been actively carried out to perform decentralized optimization processing over multiagent networks. In this article, we introduce the application of distributed optimization to cooperative control in wind farms.

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Proposed by US (Ultrasonics)
  • Toshio TSUCHIYA
    2021 Volume 14 Issue 3 Pages 181-193
    Published: January 01, 2021
    Released on J-STAGE: January 01, 2021

    Currently, deep-sea exploration in Japan is conducted almost exclusively by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). JAMSTEC, which was established in 1971, owned no vessels until the 1980s and could not expect much budget for deep-sea exploration from the government. Under such circumstances, we introduced the first US-made deep-sea exploration sonar system in Japan and have been operating it while learning related techniques. I will also explain we to successfully discovered a sunken ship (from World War II) and a crashed rocket engine using various domestically produced sonars.

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Proposed by IMQ (Image Media Quality)
  • Kenji SUGIYAMA
    2021 Volume 14 Issue 3 Pages 194-204
    Published: January 01, 2021
    Released on J-STAGE: January 01, 2021

    The use of digital video was very limited until 20 years ago. We cannot now imagine a society without it. The wide spread use of digital video is a result of the realigation of significant information compression by high-efficiency coding. However, people are not conscious of information being compressed. Video coding is a “result of wisdom”, and, its technology has reached a high level. Herein we review how this technology advanced. First, I explain its standardization and application. Focusing on the motion compensated interframe prediction and discrete cosine transform, which long been the mainstream for long. I explain politely why it's efficient. Further more, I describe how it has been improved as well as how to encode efficiency.

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Proposed by SITE (Social Implications of Technology and Information Ethics)
  • Takahiro HAGA
    2021 Volume 14 Issue 3 Pages 205-216
    Published: January 01, 2021
    Released on J-STAGE: January 01, 2021

    In this paper, we explain in detail “online education in digitization of education” and the handling of copyrights, which attracted unprecedented attention not only from educators but also from the general public as part of the response to the COVID-19 pandemic in the 2020 academic year. The challenges and prospects for the future. The handling of copyright will be explained referring to the “Points of Discussion on the Formulation of Guidelines for the Operation of the Revised Copyright Act, Article 35” published by the “Forum of Interested Parties on Educational Use of Copyrighted Works” in January 2020.

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Proposed by IT (Information Theory)
  • —Celebrating Receipt of Japan Prize by Prof. Robert G. Gallager
    Hironori UCHIKAWA
    2021 Volume 14 Issue 3 Pages 217-228
    Published: January 01, 2021
    Released on J-STAGE: January 01, 2021

    Robert G. Gallager, Professor Emeritus at Massachusetts Institute of Technology, was awarded the 2020 Japan Prize. The low-density parity-check code (LDPC code), the award's subject, is an error correction code proposed by Professor, Gallager in his doctoral thesis in 1960. It has now become an essential fundamental technology that supports our modern digital life. In this article, we describe the LDPC codes that can derive the optimal decoding algorithm in probabilistic inference. Furthermore, in this article we also introduce a practical LDPC code construction.

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Proposed by NLP (Nonlinear Problems)
  • Tohru IKEGUCHI
    2021 Volume 14 Issue 3 Pages 229-238
    Published: January 01, 2021
    Released on J-STAGE: January 01, 2021

    The Bernoulli shift map is one of the nonlinear dynamical systems that show chaotic responses. The Bernoulli shift map is a piecewise linear dynamic system, but because of its simplicity of description, it is used in various situations. On the other hand, the essence of the dynamics of the Bernoulli shift map is that it doubles the state value. In other words, we must be careful when we implement the Bernoulli shift map on the current digital computers that use binary systems. In this article, we first describe an issue in the implementation of the response of the Bernoulli shift map with a digital computer. To solve this issue, we introduced two methods and investigated their performance: the first one is to give a small displacement to the slope of the map and the second one is to give a small displacement to the state value of the map. We evaluated these two methods by estimating Lyapunov exponents and invariant measures. In addition, we generated chaotic time series generated from the Bernoulli shift map by the methods and investigated the performance of the obtained chaotic time series as pseudorandom numbers, presenting the results of applying the NIST test to the chaotic times series.

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