Takaaki Ohnishi

Profile Information

Affiliation

Graduate School of Artificial Intelligence and Science, Rikkyo University

Degree

博士(科学)(東京大学)

Researcher number

10376387

J-GLOBAL ID

201801017592544995

researchmap Member ID

B000301233

Research Areas

• Other / Other /

Research History

• Apr, 2023 - Present

  専門研究員(兼任), 金融庁金融研究センター
• Jul, 2022 - Present

  リサーチフェロー(兼任), 東京大学生産技術研究所
• Apr, 2020 - Present

  教授, 立教大学大学院人工知能科学研究科
• Nov, 2013 - Mar, 2020

  The Graduate School of Information Science and Technology, Department of Mathematical Informatics, The University of Tokyo
• Oct, 2013 - Mar, 2020

  The Graduate School of Information Science and Technology, The University of Tokyo
• Aug, 2013 - Sep, 2013

  Institute of Statistical Research
• Jan, 2012 - Sep, 2013

  主任研究員, 一般財団法人キヤノングローバル戦略研究所
• Oct, 2009 - Jul, 2013

  Division of Economics, Graduate School, The University of Tokyo
• Jun, 2009 - Dec, 2011

  研究員, 一般財団法人キヤノングローバル戦略研究所
• Jun, 2009 - Oct, 2009

  School of Legal and Political Studies, Graduate Schools for Law and Politics, The University of Tokyo
• Apr, 2004 - May, 2009

  School of Legal and Political Studies, Graduate Schools for Law and Politics, The University of Tokyo

Education

• Apr, 2001 - Mar, 2004

  Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo
• Apr, 1999 - Mar, 2001

  The Graduate School of Engineering, The University of Tokyo
• Apr, 1995 - Mar, 1999

  University of Tsukuba

Papers

• Temporal invariance of centrality correlations and hierarchical topology in evolving cross-shareholding networks in Japan (2001–2023)

  Shinichiro Tanabe, Takaaki Ohnishi

  PLOS One, 21(3) e0331561-e0331561, Mar 25, 2026 Peer-reviewedLast author
• Large Language Model-Based Topic Modeling for Analyzing Research Trends in Polymer Science Literature

  Yoshifumi Amamoto, Takaaki Ohnishi

  Materials Today Communications, 52 114945, Mar, 2026 Peer-reviewed
• Learning Characteristics of Reverse Quaternion Neural Network

  Shohgo Yamauchi, Tohru Nitta, Takaaki Ohnishi

  2025 International Joint Conference on Neural Networks (IJCNN), 1-8, Nov, 2025 Peer-reviewedLast author
• Natural language processing-based topic models for analyzing trends in polymer science

  Yoshifumi Amamoto, Yoh-ichi Mototake, Takaaki Ohnishi

  Polymer Journal, 57 1033-1041, May 29, 2025 Peer-reviewed
• Classification of Sleep Stages Based on Quantile Graphs from Mouse EEG

  Kazuki Koyama, Masanori Sakaguchi, Takaaki Ohnishi

  In: Complex Networks and Their Applications XIII. COMPLEX NETWORKS 2024. Studies in Computational Intelligence, Springer, 1190 127-138, Apr 3, 2025 Peer-reviewed
• Analysis of Cross-Shareholding Network of Japanese Listed Companies

  Shinichiro Tanabe, Takaaki Ohnishi

  In: Complex Networks and Their Applications XIII. COMPLEX NETWORKS 2024. Studies in Computational Intelligence, Springer, 1188 187-199, Mar, 2025 Peer-reviewed
• Analysis of LLMs for RDF Triple Generation: Semantic and Syntactic Evaluation Using WebNLG

  Soichi Onozuka, Takaaki Ohnishi

  2025 19th International Conference on Semantic Computing (ICSC), 136-143, Feb 3, 2025 Peer-reviewedLast author
• A Noise-Robust Approach to Estimate Dimension of Sleep EEG in Mice Using Permutation Entropy

  Kazuki Koyama, Masanori Sakaguchi, Takaaki Ohnishi

  2024 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), 1-8, Jun 30, 2024 Peer-reviewed
• Exogenous and endogenous factors affecting stock market transactions: A Hawkes process analysis of the Tokyo Stock Exchange during the COVID-19 pandemic

  Mariko I. Ito, Yudai Honma, Takaaki Ohnishi, Tsutomu Watanabe, Kazuyuki Aihara

  PLOS ONE, 19(4) e0301462-e0301462, Apr 17, 2024 Peer-reviewed
• Gaussian hierarchical latent Dirichlet allocation: Bringing polysemy back

  Takahiro Yoshida, Ryohei Hisano, Takaaki Ohnishi

  PLOS ONE, 18(7) e0288274-e0288274, Jul 12, 2023 Peer-reviewed
• Fluctuation in Grocery Sales by Brand: An Analysis Using Taylor’s Law

  Kazuki Koyama, Mariko I. Ito, Takaaki Ohnishi

  The Review of Socionetwork Strategies, 16(2) 417-430, Oct, 2022 Peer-reviewed
• Fluctuations in the Number of Stores by Industry During the COVID-19 Pandemic Based on Japanese Phone Book Entries

  Saki Saito, Mariko I. Ito, Takaaki Ohnishi

  The Review of Socionetwork Strategies, 16(2) 545-557, Oct, 2022 Peer-reviewed
• ID-POS Data Analysis Using TV Commercial Viewership Data

  Taizo Horikomi, Mariko I. Ito, Takaaki Ohnishi

  The Review of Socionetwork Strategies, 16(2) 431-451, Oct, 2022 Peer-reviewed
• Visualizing Social and Behavior Change due to the Outbreak of COVID-19 Using Mobile Phone Location Data

  Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe

  New Generation Computing, 39(3-4) 453-468, Nov, 2021 Peer-reviewed
• Co-occurrence network of TV advertisements revealing Japanese lifestyle

  Mariko I. Ito, Takaaki Ohnishi

  Applied Network Science, 6(1) 1-19, Jul, 2021 Peer-reviewed
• Metabolic fingerprints of fear memory consolidation during sleep

  Iyo Koyanagi, Kazuhiro Sonomura, Toshie Naoi, Takaaki Ohnishi, Naoko Kaneko, Kazunobu Sawamoto, Tak-Aki Sato, Masanori Sakaguchi

  Molecular Brain, 14(30), Feb, 2021 Peer-reviewed
• Uncovering the Image Structure of Japanese TV Commercials Through a Co-occurrence Network Representation

  Mariko I. Ito, Takaaki Ohnishi

  In: Complex Networks and Their Applications IX. COMPLEX NETWORKS 2020. Studies in Computational Intelligence, Springer, 943 273-283, 2021 Peer-reviewed
• Nondiagonal Mixture of Dirichlet Network Distributions for Analyzing a Stock Ownership Network

  Wenning Zhang, Ryohei Hisano, Takaaki Ohnishi, Takayuki Mizuno

  In: Complex Networks and Their Applications IX. COMPLEX NETWORKS 2020. Studies in Computational Intelligence, Springer, 943 75-86, 2021 Peer-reviewed
• Topological Data Analysis of Microdomain Patterns of Block Copolymer

  Y. Mototake, S. Yamanaka, T. Aoyagi, T. Ohnishi, K. Fukumizu

  Proceedings of the 2020 International Symposium on Nonlinear Theory and its Applications (NOLTA2020), 517-520, Nov, 2020 Peer-reviewed
• Quantification of microphase separated structures from the viewpoint of multifractal

  Proceedings of the 2020 International Symposium on Nonlinear Theory and its Applications (NOLTA2020), 480-483, Nov, 2020 Peer-reviewed

Misc.

• メリットオーダーモデルに基づく日本卸電力市場の価格構造分析

  大谷 俊介, 大西 立顕

  人工知能学会第二種研究資料 ビジネス・インフォマティクス研究会 SIG-BI, 2026(BI-028) 16, Mar, 2026 Last author
• 株式市場のトレンド転換局面における取引量変化の外因性・内因性分析

  須藤 実, 大西 立顕

  人工知能学会第二種研究資料 ビジネス・インフォマティクス研究会 SIG-BI, 2026(BI-028) 8, Mar, 2026 Last author
• 持ち合い解消下での日本企業株所有ネットワークの中心性指標の時間変化

  田邊 真一郎, 大西 立顕

  人工知能学会第二種研究資料 ビジネス・インフォマティクス研究会 SIG-BI, 2026(BI-028) 2, Mar, 2026 Last author
• テレビニュース報道の文章埋め込みによるトピック解析

  齋藤淳平, 大西立顕

  じんもんこん2025論文集, 2025 101-108, Dec, 2025
• LNG価格を用いたJEPXスポット価格の平均回帰過程モデル

  大谷俊介, 大西立顕

  信学技報 NLP2024-144, 124(432) 184-190, Mar, 2025
• 自己励起と自己変調による東証株式の取引点過程分析

  須藤 実, 大西立顕

  信学技報 NLP2024-143, 124(432) 177-183, Mar, 2025
• 日本の株式持ち合いネットワークの構造分析

  田邊真一郎, 大西立顕

  信学技報 NLP2024-118, 124(432) 51-57, Mar, 2025
• 東京証券取引所における複数カーネルHawkes過程による取引クラスター特性の分析

  須藤 実, 大西 立顕

  人工知能学会研究会資料 SIG-FIN-033, 122-129, Oct, 2024
• データサイエンスの保健医療への応用

  大西立顕

  社会保障研究, 9(1) 33-44, Jul, 2024
• ラプラシアン行列を用いたTV-CM出稿の企業間ネットワークの構造変化の分析

  田邊 真一郎, 大西 立顕

  人工知能学会第二種研究資料 ビジネス・インフォマティクス研究会 SIG-BI 024-11, 1-5, Mar, 2024
• 地域メッシュ内店舗・施設数の成長率分布に観られる統計的性質

  土屋健, 大西立顕

  進化経済学会論集 第28集, 609-628, Mar, 2024
• TVメタデータと階層的クラスタリングを用いた番組提供企業の共起ネットワークの特徴分析

  田邊真一郎, 大西立顕

  進化経済学会論集 第28集, 629-640, Mar, 2024
• 遅れ時間座標系におけるマウスの脳波時系列データの順列エントロピーによる評価

  小山一樹, 坂口昌徳, 大西立顕

  信学技報 NLP2023-148, 123(428) 119-122, Mar, 2024 Last author
• ネット掲示板発言小町のLDAによるトピック分析

  川口 裕靖, 大西 立顕

  研究報告人文科学とコンピュータ(CH), 2024-CH-134(6) 1-8, Feb, 2024 Corresponding author
• 順列エントロピーによるマウスの睡眠状態判定の精度向上

  小山一樹, 坂口昌徳, 大西立顕

  研究報告数理モデル化と問題解決(MPS), 2024-MPS-147(27) 1-6, Feb, 2024 Corresponding author
• フラクタル次元を用いた日本全国の業種ごとの都市構造分析

  土屋 健, 大西 立顕

  信学技報 NLP2023-102, 123(NLP-354) 90-93, Jan, 2024
• 睡眠ステージを特徴づけるマウスの脳波時系列の相関次元

  小山一樹, 坂口昌徳, 大西立顕

  信学技報 NLP2022-122, 122(436) 75-80, Mar, 2023
• ニコニコ動画を用いた経済トピック時系列の解析

  川口裕靖, 大西立顯

  進化経済学会論集 第27集, 34-46, Mar, 2023
• 中古マンションの価格と面積の関係の地域性

  柴田紘希, 大⻄立顕

  進化経済学会論集 第27集, 18-33, Mar, 2023
• 東証の株式市場における取引点過程の時系列解析

  伊藤真利子, 大西立顕, 本間裕大

  進化経済学会論集 第27集, 1-16, Mar, 2023

Presentations

• Indicator of the Number of Stores and Facilities Suitable for Urban Population Using Scaling Exponents

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  Social Informatics 2019, Nov, 2019
• Applying a Change-point Detection Method to Housing Market Data

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  Conference on Complex Systems 2019, Oct, 2019
• Dimension Reduction of Molecular Fingerprints

  Takaaki Ohnishi, Mariko Ito

  Conference on Complex Systems 2019, Oct, 2019
• Using two-dimensional Kolmogorov-Smirnov statistics to characterize allometric scaling between population and number of facilities

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  FENS 2019 - 10th Polish Symposium on Physics in Economy and Social Sciences, Jul, 2019
• Continuous increases or decreases in city sizes observed in Japanese telephone directory data

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  DPG Spring Meeting, Apr 2, 2019
• Directional patterns of city size changes in Japan

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  The Computational Social Science Society of the Americas CSS 2018, Oct, 2018
• The dynamics of city growth observed in Japanese telephone directory data

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  Conference on Complex Systems 2018, Sep, 2018
• Statistical laws of urban development and decline

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  The 23rd Annual Workshop on Economic Science with Heterogeneous Interacting Agents (WEHIA 2018), Jun, 2018
• Quantification of spatial collocation patterns of shops and facilities using the two-dimensional Kolmogorov-Smirnov statistic

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  13th German Probability and Statistics Days 2018, Feb, 2018
• Three State Model for Temporal Network Change Detection

  Chikara Mizokami, Takaaki Ohnishi

  NetSci-X 2018: International School and Conference on Network Science, Jan, 2018
• Use of the two-dimensional Kolmogorov-Smirnov test to measure spatial concentration in geospatial data

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  11th International Conference on Computational and Financial Econometrics (CFE 2017), Dec, 2017
• Revealing Persistent Structure of International Trade by Nonnegative Matrix Factorization

  Chikara Mizokami, Takaaki Ohnishi

  COMPLEX NETWORKS 2017: The 6th International Conference on Complex Networks and Their Applications, Nov, 2017
• Irresponsible communities in global supply chain

  Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe

  COMPLEX NETWORKS 2017: The 6th International Conference on Complex Networks and Their Applications, Nov, 2017
• International Trade Relationship from a Multilateral Point of View

  Hiroshi Iyetomi, Yuichi Ikeda, Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe

  COMPLEX NETWORKS 2017: The 6th International Conference on Complex Networks and Their Applications, Nov, 2017
• How to guard company's supply-chain risks by global inter-firm relationships

  Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe

  Conference on Complex Systems 2017, Sep, 2017
• Characteristic Spatial Interaction between Shops and Facilities in Japan

  Takaaki Ohnishi, Takayuki Mizuno, Tsutomu Watanabe

  Conference on Complex Systems 2017, Sep, 2017
• Using Network Motif Analysis to Characterize the International Trade Network

  T. Ohnishi, T. Mizuno, Y. Ikeda, H. Iyetomi, T. Watanabe

  SigmaPhi2017, Jul, 2017
• Exploiting global buyer-supplier networks to improve supply chain due diligence

  T. Mizuno, T. Ohnishi, T. Watanabe

  SigmaPhi2017, Jul, 2017
• A countermeasure for supply-chain risks based on structure of global buyer-supplier network

  Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe

  8th Conference on Complex Networks (CompleNet'17), Mar, 2017
• Daily living area detection using mobility network map equation

  Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe

  COMPLEX NETWORKS 2016: The 5th International Conference on Complex Networks and Their Applications, Nov, 2016

Books and Other Publications

• ネットワーク学習から経済と法分析へ

  久野, 遼平, 大西, 立顕, 渡辺, 努

  サイエンス社, Jun, 2024 (ISBN: 9784781916040)

Professional Memberships

• JAPAN ASSOCIATION FOR EVOLUTIONARY ECONOMICS
• INFORMATION PROCESSING SOCIETY OF JAPAN
• JAPANESE ECONOMIC ASSOCIATION
• THE PHYSICAL SOCIETY OF JAPAN

Research Projects

• 自己・相互励起型点過程を用いた経済・社会の内生的変動の変化点検知

  科学研究費助成事業, 基盤研究(B), 日本学術振興会, Apr, 2022 - Mar, 2027

  大西 立顕
• 地理空間ビッグデータとスパコンを用いた高齢者の生活基盤評価

  科学研究費補助金 挑戦的研究(萌芽), 日本学術振興会, Jun, 2019 - Mar, 2022

  大西 立顕
• 複雑ネットワーク解析に基づく物質・材料探索

  科学研究費補助金 新学術領域研究(研究領域提案型), 文部科学省, Apr, 2017 - Mar, 2022

  大西立顕
• 人口・産業集積の時空間ビッグデータにみられる相転移挙動の計算科学的研究

  科学研究費補助金 基盤研究(B) (一般), 日本学術振興会, Apr, 2016 - Mar, 2020

  大西立顕
• 地域社会における生活基盤の持続可能性指標の開発

  課題設定による先導的人文学・社会科学研究推進事業 実社会対応プログラム, 日本学術振興会, Oct, 2015 - Sep, 2018

  大西立顕
• データ駆動型統計学の可能性:動的で複雑な経済・社会現象の帰納的理解に挑む

  科学研究費補助金 挑戦的萌芽研究, 日本学術振興会, Apr, 2014 - Mar, 2016

  大西立顕
• 大規模経済データにみられる相転移挙動の計算科学的研究

  科学研究費補助金 若手研究(A), 日本学術振興会, Apr, 2011 - Mar, 2015

  大西立顕
• 計算集約的経済分析の可能性:大変動・非定常・非線形を前提とした正確な実証分析

  科学研究費補助金 挑戦的萌芽研究, 日本学術振興会, Apr, 2012 - Mar, 2013

  大西立顕
• 経済現象に潜む静的・動的臨界ゆらぎの実証的観測と発生機構の解明

  科学研究費補助金 若手研究(B), 日本学術振興会, Apr, 2008 - Mar, 2011

  大西立顕