Updated on 2026/08/07

写真a

 
NISHIYAMA DAIKI
 
Organization
School of Computing Specially Appointed Assistant Professor
Title
Specially Appointed Assistant Professor
Contact information
メールアドレス
External link

Degree

  • Doctor of Engineering ( 2026.3   Institute of Science Tokyo )

  • Master of Engineering ( 2023.3   University of Tsukuba )

  • Bachelor of Information Engineering ( 2021.3   University of Tsukuba )

Research Interests

  • 説明可能AI

  • Machine Learning

  • AIセキュリティ

  • Trustworthy AI

  • Computational Pathology

Research Areas

  • Informatics / Intelligent informatics

Education

  • Institute of Science Tokyo   School of Computing   Graduate major in Artificial Intelligence, Department of Computer Science

    2023.4 - 2026.3

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    Country: Japan

    Notes: WISE Program for Super Smart Society

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  • University of Tsukuba   Graduate School of Science and Technology   Master's Program in Computer Science, Degree Programs in Systems and Information Engineering

    2021.4 - 2023.3

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    Country: Japan

    Notes: Master of Engineering

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  • University of Tsukuba   School of Informatics, College of Information Science

    2017.4 - 2021.3

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    Country: Japan

    Notes: Bachelor of Information Engineering

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Research History

  • Institute of Science Tokyo   School of Computing   Specially Appointed Assistant Professor

    2026.4

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  • Japan Society for the Promotion of Science   Research Fellow DC2

    2024.4 - 2026.3

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  • RIKEN   Center for Advanced Intelligence Project (AIP)   Part-time worker

    2021.5 - 2026.3

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Papers

  • Explainable Classifier for Malignant Lymphoma Subtyping via Cell Graph and Image Fusion Reviewed

    Daiki Nishiyama, Hiroaki Miyoshi, Noriaki Hashimoto, Koichi Ohshima, Hidekata Hontani, Ichiro Takeuchi, Jun Sakuma

    Medical Image Computing and Computer Assisted Intervention – MICCAI 2025. Lecture Notes in Computer Science   320 - 330   2025.9

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    Authorship:Lead author, Corresponding author   Publisher:Springer Nature Switzerland  

    Malignant lymphoma subtype classification directly impacts treatment
    strategies and patient outcomes, necessitating classification models that
    achieve both high accuracy and sufficient explainability. This study proposes a
    novel explainable Multi-Instance Learning (MIL) framework that identifies
    subtype-specific Regions of Interest (ROIs) from Whole Slide Images (WSIs)
    while integrating cell distribution characteristics and image information. Our
    framework simultaneously addresses three objectives: (1) indicating appropriate
    ROIs for each subtype, (2) explaining the frequency and spatial distribution of
    characteristic cell types, and (3) achieving high-accuracy subtyping by
    leveraging both image and cell-distribution modalities. The proposed method
    fuses cell graph and image features extracted from each patch in the WSI using
    a Mixture-of-Experts (MoE) approach and classifies subtypes within an MIL
    framework. Experiments on a dataset of 1,233 WSIs demonstrate that our approach
    achieves state-of-the-art accuracy among ten comparative methods and provides
    region-level and cell-level explanations that align with a pathologist's
    perspectives.

    DOI: 10.1007/978-3-032-05162-2_31

    arXiv

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  • CAMRI Loss: Improving the Recall of a Specific Class without Sacrificing Accuracy Reviewed

    Daiki NISHIYAMA, Kazuto FUKUCHI, Youhei AKIMOTO, Jun SAKUMA

    IEICE Transactions on Information and Systems   E106.D ( 4 )   523 - 537   2023.4

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    Authorship:Lead author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:Institute of Electronics, Information and Communications Engineers (IEICE)  

    DOI: 10.1587/transinf.2022edp7200

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  • CAMRI Loss: Improving Recall of a Specific Class without Sacrificing Accuracy Reviewed

    Daiki Nishiyama, Kazuto Fukuchi, Youhei Akimoto, Jun Sakuma

    Proceedings of 2022 International Joint Conference on Neural Networks (IJCNN)   2022.7

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    Authorship:Lead author, Corresponding author   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/ijcnn55064.2022.9892108

    DOI: 10.48550/arXiv.2209.10920

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MISC

  • 法令文の可読性向上のための定義規定・略称規定における文型定義及びパターンベースの正式名称・略称抽出手法

    北野尚樹, 西山大輝

    言語処理学会第31回年次大会 発表論文集   2243 - 2248   2025.3

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    Language:Japanese   Publishing type:Research paper, summary (national, other academic conference)  

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  • Adversarial Attacks on Hidden Tasks in Multi-Task Learning

    Yu Zhe, Rei Nagaike, Daiki Nishiyama, Kazuto Fukuchi, Jun Sakuma

    2024.5

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    Publisher:arXiv  

    Deep learning models are susceptible to adversarial attacks, where slight
    perturbations to input data lead to misclassification. Adversarial attacks
    become increasingly effective with access to information about the targeted
    classifier. In the context of multi-task learning, where a single model learns
    multiple tasks simultaneously, attackers may aim to exploit vulnerabilities in
    specific tasks with limited information. This paper investigates the
    feasibility of attacking hidden tasks within multi-task classifiers, where
    model access regarding the hidden target task and labeled data for the hidden
    target task are not available, but model access regarding the non-target tasks
    is available. We propose a novel adversarial attack method that leverages
    knowledge from non-target tasks and the shared backbone network of the
    multi-task model to force the model to forget knowledge related to the target
    task. Experimental results on CelebA and DeepFashion datasets demonstrate the
    effectiveness of our method in degrading the accuracy of hidden tasks while
    preserving the performance of visible tasks, contributing to the understanding
    of adversarial vulnerabilities in multi-task classifiers.

    DOI: 10.48550/ARXIV.2405.15244

    arXiv

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    Other Link: http://arxiv.org/pdf/2405.15244v2

  • マルチタスク学習における隠れたタスクに対する敵対的攻撃

    永池礼, 西山大輝, 秋本洋平, 福地一斗, 佐久間淳

    2024年暗号と情報セキュリティシンポジウム(SCIS2024)   2024.1

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    Language:Japanese   Publisher:電子情報通信学会 情報セキュリティ研究専門委員会(ISEC研)  

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  • CAMRI Loss: Improving the Recall of Prescribed Classes without Sacrificing Accuracy

    37th   2023

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  • CAMRI Loss: Improving Recall of a Specific Class without Sacrificing Accuracy

    Daiki Nishiyama, Kazuto Fukuchi, Youhei Akimoto, Jun Sakuma

    2022.9

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    Authorship:Lead author  

    In real-world applications of multi-class classification models,
    misclassification in an important class (e.g., stop sign) can be significantly
    more harmful than in other classes (e.g., speed limit). In this paper, we
    propose a loss function that can improve the recall of an important class while
    maintaining the same level of accuracy as the case using cross-entropy loss.
    For our purpose, we need to make the separation of the important class better
    than the other classes. However, existing methods that give a class-sensitive
    penalty for cross-entropy loss do not improve the separation. On the other
    hand, the method that gives a margin to the angle between the feature vectors
    and the weight vectors of the last fully connected layer corresponding to each
    feature can improve the separation. Therefore, we propose a loss function that
    can improve the separation of the important class by setting the margin only
    for the important class, called Class-sensitive Additive Angular Margin Loss
    (CAMRI Loss). CAMRI loss is expected to reduce the variance of angles between
    features and weights of the important class relative to other classes due to
    the margin around the important class in the feature space by adding a penalty
    to the angle. In addition, concentrating the penalty only on the important
    classes hardly sacrifices the separation of the other classes. Experiments on
    CIFAR-10, GTSRB, and AwA2 showed that the proposed method could improve up to
    9% recall improvement on cross-entropy loss without sacrificing accuracy.

    DOI: 10.1587/transinf.2022EDP7200

    arXiv

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    Other Link: http://arxiv.org/pdf/2209.10920v1

  • CAMRI Loss: Class-wise Additive Angular Margin Loss for Improving Recall of a Specific Class

    電子情報通信学会技術研究報告(Web)   121 ( 321(IBISML2021 18-29) )   2022

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    Authorship:Lead author  

    J-GLOBAL

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Presentations

  • Embedding Meets PMI: Advancing Researcher Profiling for Topic-Centric Network Using Open Data Catalogue International conference

    Mikiko Tanifuji, Masaharu Hayashi, Masashi Ooka, Daitetsu Sato, Hiroyuki Osone, Daiki Nishiyama

    The 25th Research Data Alliance (RDA) Plenary Meeting, International Data Week (IDW 2025)  2025.10  Research Data Alliance (RDA)

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    Language:English   Presentation type:Poster presentation  

    Venue:Brisbane   Country:Australia  

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  • Explainable Classifier for Malignant Lymphoma Subtyping via Cell Graph and Image Fusion

    Daiki Nishiyama, Hiroaki Miyoshi, Noriaki Hashimoto, Koichi Ohshima, Hidekata Hontani, Ichiro Takeuchi, Jun Sakuma

    Medical Image Computing and Computer Assisted Intervention – MICCAI 2025. Lecture Notes in Computer Science  2025.9  Springer Nature Switzerland

     More details

    Event date: 2025.9

    Malignant lymphoma subtype classification directly impacts treatment
    strategies and patient outcomes, necessitating classification models that
    achieve both high accuracy and sufficient explainability. This study proposes a
    novel explainable Multi-Instance Learning (MIL) framework that identifies
    subtype-specific Regions of Interest (ROIs) from Whole Slide Images (WSIs)
    while integrating cell distribution characteristics and image information. Our
    framework simultaneously addresses three objectives: (1) indicating appropriate
    ROIs for each subtype, (2) explaining the frequency and spatial distribution of
    characteristic cell types, and (3) achieving high-accuracy subtyping by
    leveraging both image and cell-distribution modalities. The proposed method
    fuses cell graph and image features extracted from each patch in the WSI using
    a Mixture-of-Experts (MoE) approach and classifies subtypes within an MIL
    framework. Experiments on a dataset of 1,233 WSIs demonstrate that our approach
    achieves state-of-the-art accuracy among ten comparative methods and provides
    region-level and cell-level explanations that align with a pathologist's
    perspectives.

    researchmap

  • 法令文の可読性向上のための定義規定・略称規定における文型定義及びパターンベースの正式名称・略称抽出手法

    北野尚樹, 西山大輝

    言語処理学会第31回年次大会 発表論文集  2025.3 

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    Event date: 2025.3

    Language:Japanese  

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  • 悪性リンパ腫の病理画像分類における細胞に基づく統計的特徴解析と説明可能な分類モデル Invited

    西山 大輝

    第6回日本メディカルAI学会学術集会  2024.6 

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    Event date: 2024.6

    Presentation type:Symposium, workshop panel (nominated)  

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  • マルチタスク学習における隠れたタスクに対する敵対的攻撃

    永池礼, 西山大輝, 秋本洋平, 福地一斗, 佐久間淳

    2024年暗号と情報セキュリティシンポジウム(SCIS2024)  2024.1  電子情報通信学会 情報セキュリティ研究専門委員会(ISEC研)

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    Event date: 2024.1

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • CAMRI Loss: Improving the Recall of Prescribed Classes without Sacrificing Accuracy

    2023 

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    Event date: 2023

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  • CAMRI Loss: Improving Recall of a Specific Class without Sacrificing Accuracy

    Daiki Nishiyama, Kazuto Fukuchi, Youhei Akimoto, Jun Sakuma

    Proceedings of 2022 International Joint Conference on Neural Networks (IJCNN)  2022.7  IEEE

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    Event date: 2022.7

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  • CAMRI Loss: Class-wise Additive Angular Margin Loss for Improving Recall of a Specific Class

    電子情報通信学会技術研究報告(Web)  2022 

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    Event date: 2022

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  • Class-Sensitive Loss: Improving the Recall of a Particular Class without Sacrificing Accuracy.

    西山大輝, 福地一斗, 秋本洋平, 佐久間淳

    第24回情報論的学習理論ワークショップ  2021.11  電子情報通信学会

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    Language:Japanese   Presentation type:Poster presentation  

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Research Projects

  • 複数の防御結果を統合利用する属性推定攻撃に対する防御設計

    Grant number:26K25587  2026.7 - 2028.3

    日本学術振興会  科学研究費助成事業  研究活動スタート支援

    西山 大輝

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    Grant amount:\2730000 ( Direct Cost: \2100000 、 Indirect Cost:\630000 )

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  • Reliable Classification Model for Explaining Relationships between Objects in Images

    Grant number:24KJ1049  2024.4 - 2026.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for JSPS Fellows

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    Grant amount:\1500000 ( Direct Cost: \1500000 )

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Other

  • Registered Information Security Specialist

    2023.4

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  • 中学校教諭一種免許状(数学)

    2023.3

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  • 高等学校教諭一種免許状(数学・情報)

    2023.3

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Social Activities

  • つくば市における中学生向けサーバー・ネットワーク教育支援

    Role(s): Lecturer, Advisor, Planner, Organizing member

    つくば市総合教育研究所  インデペンデンス・サーバー・デイ  つくば市総合教育研究所  2019.8

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    Audience: Junior students, Teachers, Governmental agency

    Type:Seminar, workshop

    つくば市内の中学生を対象としたサーバー・ネットワーク教育イベント「インデペンデンス・サーバー・デイ」に、2019年度より継続して参画。参加者が1人1台のサーバーと固定グローバルIPアドレスを用いて、Linux、ネットワーク、Webサーバー、セキュリティ等を学ぶ講義・実習において、講師や企画運営および受講者支援を担当している。

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Media Coverage

  • 研究開発がドキュメンタリーとして特集・開発コンテストにて優勝 TV or radio program

    AbemaTV  TDK presents 学生イノベーションバトル そのヒラメキで世界を変えろ  全6回  2020.3

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    Author:Other 

    AbemaTV配信番組『TDK presents 学生イノベーションバトル そのヒラメキで世界を変えろ』に、筑波大学チーム「Dr.B」として出演。外国人旅行者の医療費未払い問題の解決を目的として、暗号資産を活用した医療費決済サービスを開発した。約4か月間の研究開発・検証・発表の過程がドキュメンタリーとして特集され、全7チームによる開発コンテストで優勝した。

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