通信情報システム専攻 2015年度談話会の概要

第1回 (日本語開催)

日時
2015年4月17日(金) 16:30-18:00
場所
  • 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • 生存圏S-143H遠隔講義室
  • 京都大学YRPモバイルラボ (横須賀)
※YRPで聴講される場合は世話人まで事前にご連絡ください。
講演者
廣瀬 哲也 (神戸大学大学院工学研究科・准教授)
講演題目
超低電力CMOS LSIのためのエネルギーハーベスティングシステムの設計と実装
概要
次世代超低電力CMOS LSIのエネルギー源として,エネルギーハーベスティング(Energy Harvesting)技術が注目されている.バッテリレスLSIの市場規模は今後大きく拡大すると期待されている.しかし,ハーベスタ(Harvester)の出力電圧は極めて低く,その出力電圧をそのままLSIの電源として利用することはできない.そこで,ハーベスタの出力電圧を高効率で昇圧するパワーマネージメント回路が必須となる.本講演では,ハーベスタの出力電圧を高効率に昇圧する昇圧コンバータついて議論する.

第2回 (英語開催)

日時
2015年5月15日(金) 16:30-18:00
場所
  • 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • 生存圏S-143H遠隔講義室
  • 京都大学YRPモバイルラボ (横須賀)
※YRPで聴講される場合は世話人まで事前にご連絡ください。
講演者
Dr. Sachie Shiomi (Research Institute for Sustainable Humanosphere, Kyoto University)
講演題目
Precision measurement of gravity and its applications to geophysics
概要
The history of measuring gravity begun, more than 400 years ago, with Galileo Galilei's experiments, and the measurement technologies have been developed since then. Nowadays, the purpose of measuring gravity, with high precision, is twofold. One is to understand the properties of gravity. The other is to detect underground structures. The former is the investigation of gravity itself, such as testing Albert Einstein's theory of general relativity. The latter is practical applications, such as underground resource explorations and geophysical surveys. The required sensitivity for the former is obviously higher than the latter, by at least several orders of magnitude, but many of the measurement technologies are fundamentally the same. In this talk, I will present an overview of the modern technologies of precise gravity measurements, both on ground and in space, and discuss the requirements on designing sensitive gravimeters.

第3回 (英語開催)

日時
2015年6月26日(金) 16:30-18:00
場所
  • [吉田] 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • [横須賀] 京都大学YRPモバイルラボ
※YRPで聴講される場合は世話人まで事前にご連絡ください。
講演者
河内谷 清久仁 博士 (日本アイ・ビー・エム(株) 東京基礎研究所 ディープ・コンピューティング&アナリティクス担当部長)
Speaker
Dr. Kiyokuni Kawachiya (Research Staff Member, Manager of Deep Computing & Analytics, IBM Research - Tokyo)
講演題目
耐故障性を備えた分散プログラミング言語X10
Title
Resilient Distributed Programming Language X10
概要
X10はIBM Researchが中心となって開発しているプログラミング言語で,言語自体が複数の計算ノードを使う「分散処理」の機能を備えていることが特徴である.本講演ではX10の分散処理機能を中心に概説する.まず,実行モデルであるAPGAS (Asynchronous Partitioned Global Address Space)について紹介し,X10の特徴的な構文であるasyncやat,分散処理のためのデータ構造であるDistArray,PlaceLocalHandle,GlobalRefなどについても,プログラム例とともに解説する.次に,分散処理において重要となる「分散GC」の仕組みや,ノード故障時にも処理を継続するための「Resilient X10」について紹介する.なお,X10はオープンソースプロジェクトとして開発されており,コードや資料は http://x10-lang.org/ から入手することができる.
Abstract
X10 is a programming language being developed by IBM Research. One of its characteristics is the support of "distributed processing" using multiple computing nodes. This talk introduces X10, mainly focusing on its distributed processing functions. First, its execution model APGAS (Asynchronous Partitioned Global Address Space) is explained, and distributed programming primitives (at, async, ...) and data structures (DistArray, PlaceLocalHandle, GlobalRef, ...) are shown with examples. Some advanced topics such as "Distributed GC" and fault tolerance support by "Resilient X10" will also be covered. X10 is an open source project and information can be got from http://x10-lang.org/

第4回 (英語開催)

日時
2015年7月17日(金) 16:30-18:00
場所
  • 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • 生存圏S-143H遠隔講義室
  • 京都大学YRPモバイルラボ (横須賀)
※YRPで聴講される場合は世話人まで事前にご連絡ください。
講演者
Dr. Wei Liu (National Institute of Information and Communications technology (NICT))
講演題目
Social ICT -- ICT for better Society
概要
Based on the convergence of cyber and physical worlds, the next generation of information and communications technology (ICT) service platform is cross-disciplinary and aims at generating and delivering valuable knowledge to support different aspects of the society. With a deep understanding of this world’s trends, we have taken up a new challenge of social renovation by ICT, i.e. "Social ICT". In this talk, we discuss the concept and typical applications of Social-ICT. Demos of our research achievements will also be shown.

第5回 (英語開催)

日時
2015年10月16日(金) 16:30-18:00
場所
  • 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • 生存圏S-143H遠隔講義室
  • 京都大学YRPモバイルラボ (横須賀)
※YRPで聴講される場合は世話人まで事前にご連絡ください。
講演者
橋本 大志 (京都大学大学院情報学研究科)
Speaker
Mr. Taishi Hashimoto (Graduate School of Informatics, Kyoto University)
講演題目
大気レーダーのための適応的ビーム形成法
Title
Adaptive beamforming techniques for atmospheric radars
概要
最近の大気レーダーの多くはアクティブフェーズドアレイ方式を採用しています.これらのシステムでは高速にビームを走査できるだけでなく,各受信チャンネルの受信信号を用いることで不要波の到来方向に応答を持たないようなビームパターンを生成することができ,この手法はAdaptive beamforming(適応的ビーム形成)と呼ばれます.本講演では,フェーズドアレイ及び適応的ビーム形成法について解説し,最近の研究成果を紹介します.また,南極昭和基地にある大型大気レーダー(PANSY)についても言及します.
Abstract
Modern atmospheric radars commonly use the active phased array system, which can rapidly change the beam direction in a very short time. In addition, by utilizing the received signals from each receiver channel, we can modify the beam pattern not to respond to those directions where undesired signals come from. This technique is called "adaptive beamforming". In this talk, we describe the basics of the phased array system and adaptive beamforming algorithm, followed by some recent studies on atmospheric radars. Also we introduce our new atmospheric radar at Syowa Station in Antarctica; the PANSY radar.

第6回 (英語開催)

日時
2015年11月13日(金) 16:30-18:00
場所
  • 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • 生存圏S-143H遠隔講義室
  • 京都大学YRPモバイルラボ (横須賀)
※YRPで聴講される場合は世話人まで事前にご連絡ください。
Speaker
Dr. Junichi Teruyama (National Institute of Informatics)
Title
Algorithms for Branching Program Satisfiability Problems
Abstract
The satisfiability problem (SAT) is one of fundamental problems in theoretical computer science. There exist many variants of SAT and they are known NP-complete, in many cases. In this talk, I focus on SAT for branching programs (BP-SAT). I will introduce the definition of branching programs and BP-SAT. After that, I will survey algorithms for BP-SAT, and present our new results. This is a joint work with Kazuhisa Seto and Atsuki Nagao.

第7回 (日本語開催)

日時
2015年12月18日(金) 16:30-18:00
場所
  • 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • 生存圏S-143H遠隔講義室
  • 京都大学YRPモバイルラボ (横須賀)
※YRPで聴講される場合は世話人まで事前にご連絡ください。
Speaker
Dr. Kosuke Tsujino (Amazon Japan)
Title
Product search in Amazon: Infrastructure and Algorithms
Abstract
Product search engines help customers make purchase decisions and thereby play a critical role in e-commerce industry. This talk introduces the basics of modern search engines, in terms of both algorithm and infrastructure. With regard to the infrastructure, the core idea for modern search engines and its distributed implementation for large-scale industrial systems is explained. Also, this talk gives an overview of our algorithmic effort towards better search relevance, which roughly means "to put good stuff on the top of the search results", with the use of machine learning and natural language processing technologies.

第8回 (英語開催)

日時
2015年1月15日(金) 16:30-18:00
場所
  • 学術情報メディアセンター南館 マルチメディア講義室202講義室
    (http://www.media.kyoto-u.ac.jp/access/#s_bldg 参照。南館館内拡大図もご参照下さい。)
  • 生存圏S-143H遠隔講義室
  • 京都大学YRPモバイルラボ (横須賀)
※YRPで聴講される場合は世話人まで事前にご連絡ください。
Speaker
Tadashi Matsumoto (Japan Advanced Institute of Science and Technology, Japan, and University of Oulu, Finland (Part time))
Title
Cooperative Communications: from the correlated source coding theorem viewpoint
Abstract

A goal of this talk is to provide audience with the knowledge about the relationship between lossy-forwarding relay systems and the Distributed Coding techniques for correlated sources.

This talk will be started by briefly reviewing the historical background and progress of Information Theory and Signal Processing for Wireless Communications. Especially, how and why iterative (turbo) decoding can achieve asymptotically the close-limit performance will be addressed. Then, the focus of this talk is shifted to cooperative communications. It is shown that performance of the conventional decode-and-forward system can significantly be improved by performing another interleaving at the relay, with which the resulting network structure is equivalent to distributed turbo code. Furthermore, since the knowledge about the bit error probability of the source-relay node can be used as the correlation between the two frames, one from the source, and the other from the relay, we can well exploit the Slepian-Wolf theorem; With the utilization of the theorem, the relay can forward the frame even though it detects errors in the information part, and the destination can recover the data losslessly.

Then, this talk further introduces the idea, from lossless-likn-design-based to lossy-based. In this part, we assume that none of the relays at the final stage has no errors in the information parts of the frames. This category of the problems belongs to Distributed Lossy Coding, represented by the Chief Executive Officer (CEO) problem, in Network Information Theory. This talk briefly explains major results of analysis we have achieved up until now, but because of the time limitation, we do not go into very deep level of mathematical derivations of the formulas.

Finally, this talk briefly introduces "Links-on-the-fly Technology for Robust, Efficient and Smart Communication in Unpredictable Environments (RESCUE) a EU FP7 ICT-2013 project, of which concept was motivated by the technological bases described above. The objective of the project is to create energy- and spectrally-efficient communication systems which are robust against unpredictable network topology changes. The origin of the project proposal is that massive earthquakes including series of aftershock hit the Tohoku and Kanto areas in Japan on March 11, 2011, followed by unprecedentedly huge Tsunami waves of up to 40 m height. After the huge devastative/disastrous event clearly indicated several limitations in operability of the conventional wireless communication systems based on the accurate link budget allocation concept and communication chain design (coding, signaling chain, as well as also higher layer protocols), and the continuation of the communication is supported by a proper handover algorithm. The systems, which are expected to keep its operability in unpredicted network damages, have to be robust against the network topology change.

The results are expected to be applicable to machine-to-machine and vehicle-to-vehicle communications as well as communication for internet-of-things since they should also require the robustness against the network topology change, and have to be highly energy-efficient. This talk provides the participants with the knowledge of technological bases towards achieving this goal, performance limit/outage derivations, and some practical coding/decoding algorithms. The issues described above are explained mainly from the viewpoint of lossless/lossy distributed correlated source coding theorems in network information theory.