Updated on 2026/04/03

写真a

 
TAKAZAWA YOTARO
 
Organization
Undergraduate School School of Business Administration Senior Assistant Professor
Title
Senior Assistant Professor
Contact information
メールアドレス
External link

Degree

  • Doctor of Engineering ( 2019.9   Tokyo Institute of Technology )

Research Areas

  • Social infrastructure (civil Engineering, architecture,disaster prevention) / Social systems engineering

  • Informatics / Information theory

Education

  • Tokyo Institute of Technology   School of Engineering   Department of Industrial Engineering and Economics

    2017.4 - 2019.9

      More details

    Country/Region: Japan

    researchmap

  • Tokyo Institute of Technology

    2015.4 - 2017.3

      More details

    Country/Region: Japan

    researchmap

  • Tokyo Institute of Technology   Faculty of Engineering

    2011.4 - 2015.3

      More details

    Country/Region: Japan

    researchmap

Research History

  • Meiji University   School of Business Administration   Senior Assistant Professor

    2023.4

      More details

    Country/Region:Japan

    researchmap

  • College of Science and Engineering College of Science and Engineering Department of Industrial and Systems Engineering Assistant Professor

    2019.10 - 2023.3

      More details

  • Ritsumeikan Asia Pacific University   College of International Management

    2023.2 - 2023.3

      More details

  • International Christian University

    2020.12 - 2023.3

      More details

  • Mercari, Inc.   AI team   Intern

    2018.10 - 2019.9

      More details

    Country/Region:Japan

    researchmap

  • PKSHA Technology Inc.   Intern

    2016.3 - 2019.8

      More details

    Country/Region:Japan

    researchmap

▼display all

Professional Memberships

Committee Memberships

  • 日本オペレーションズ・リサーチ学会   論文誌JORSJ・TORSJ 編集幹事  

    2023.12 - 2025.12   

      More details

    Committee type:Academic society

    researchmap

  • 日本オペレーションズ・リサーチ学会   庶務幹事  

    2022.4   

      More details

    Committee type:Academic society

    researchmap

Papers

  • Mixed-Integer Programming Dispatch with Courier Drop-Out Risk: Balancing Cost and Delay in Hybrid Food Delivery Fleets Reviewed

    Yotaro Takazawa, Koji Kuroda, Hotaka Hattori

    Operations Research Forum   7 ( 2 )   2026.4

     More details

    Authorship:Lead author, Last author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    Abstract

    Food delivery platforms increasingly employ hybrid workforces combining hourly-paid in-house couriers with per-delivery crowdsourced couriers. A key operational challenge is that crowdsourced couriers may drop out of the platform if they remain idle for too long, so that dispatch decisions affect not only immediate service quality but also future delivery capacity. We formalize this as a sequential decision-making problem and propose a rolling-horizon mixed-integer programming (MIP) dispatch policy with scenario-based lookahead. The MIP incorporates a drop-out constraint that links assignment timing to crowdsourced courier retention, creating a structural incentive to dispatch crowd couriers before they leave the platform. Simulation experiments calibrated with operational data from a Tokyo food delivery platform show that the proposed policy substantially reduces lateness relative to myopic bipartite matching, particularly when the platform relies heavily on crowdsourced capacity. Analysis of the results indicates that the primary mechanism is the early activation of crowdsourced couriers to maintain the available pool during peak demand, and that the policy is robust to misspecification of the drop-out parameter and does not require highly accurate demand forecasts.

    DOI: 10.1007/s43069-026-00631-4

    researchmap

    Other Link: https://link.springer.com/article/10.1007/s43069-026-00631-4

  • On Reduction of the Switching Graph Problem to the Independent Set Problem Reviewed

    Yotaro Takazawa, Shinji Mizuno

    Fields Institute Communications   167 - 173   2026.2

     More details

    Authorship:Lead author, Last author   Publishing type:Part of collection (book)   Publisher:Springer Nature Switzerland  

    DOI: 10.1007/978-3-032-03844-9_7

    researchmap

  • Are meat alternatives a moral concern? A comparison of English and Japanese tweets Reviewed

    Moena Hashimoto, Yotaro Takazawa, Kazutoshi Sasahara

    Humanities and Social Sciences Communications   11 ( 1 )   2024.9

     More details

    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1057/s41599-024-03766-z

    researchmap

    Other Link: https://www.nature.com/articles/s41599-024-03766-z

  • Approximation algorithm for the stochastic prize-collecting set multicover problem Reviewed

    Yotaro Takazawa

    Operations Research Letters   50 ( 2 )   224 - 228   2022.3

     More details

    Authorship:Lead author   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.orl.2022.02.003

    researchmap

  • An approximation algorithm for the partial covering 0–1 integer program Reviewed

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    Discrete Applied Mathematics   275   126 - 133   2020.3

     More details

    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.dam.2017.08.024

    researchmap

  • Approximation algorithms for the covering-type k-violation linear program Reviewed

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    Optimization Letters   13 ( 7 )   1515 - 1521   2019.10

     More details

    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s11590-019-01425-w

    researchmap

    Other Link: http://link.springer.com/article/10.1007/s11590-019-01425-w/fulltext.html

  • An improved approximation algorithm for the covering 0-1 integer program Reviewed

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    Pacific Journal of Optimization   15 ( 2 )   195 - 206   2019

     More details

    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    researchmap

  • A 2-APPROXIMATION ALGORITHM FOR THE MINIMUM KNAPSACK PROBLEM WITH A FORCING GRAPH Reviewed

    Yotaro Takazawa, Shinji Mizuno

    Journal of the Operations Research Society of Japan   60 ( 1 )   15 - 23   2017

     More details

    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Operations Research Society of Japan  

    DOI: 10.15807/jorsj.60.15

    researchmap

▼display all

Presentations

  • Approximation algorithms for covering problems

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    First Conference on Discrete Optimization and Machine Learning  2018.7 

     More details

    Event date: 2018.7

    Language:English  

    researchmap

  • Approximation Algorithms for the covering-type linear programming with violations

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    2018 INFORMS International Conference  2018.6 

     More details

    Event date: 2018.6

    Language:English  

    researchmap

  • An improve approximation algorithm for the covering 0-1 integer program

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    The Second Pacific Optimization Conference (POC 2017)  2017.12 

     More details

    Event date: 2017.12

    Language:English  

    researchmap

  • An approximation algorithm for the partial covering 0-1 integer program

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    SIAM Conference on Optimization  2017.5 

     More details

    Event date: 2017.5

    Language:English  

    researchmap

  • Does Morality Facilitate the Purchase of Meat Alternatives?

    2023.7 

     More details

    Presentation type:Poster presentation  

    researchmap

  • How Has Food Become a Moral Concern? A Case Study of Meat Alternatives on Twitter

    M. Hashimoto, Y. Takazawa, K. Sasahara

    8th International Conference on Computational Social Science  2022.7 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • Approximation algorithm for the stochastic prize-collecting set multicover problem

    Yotaro Takazawa

    2022.3 

     More details

    Event date: 2022.3

    Presentation type:Oral presentation (general)  

    researchmap

  • スイッチンググラフ問題の独立集合問題への帰着

    Yotaro Takazawa, Shinji Mizuno

    日本オペレーションズ・リサーチ学会春季研究発表会  2019.3 

     More details

    Event date: 2019.3

    researchmap

  • On a reduction of the weighted induced bipartite subgraph problem to the weighted independent set problem

    Yotaro Takazawa, Shinji Mizuno

    日本オペレーションズ・リサーチ学会秋季研究発表会  2018.9 

     More details

    Event date: 2018.9

    researchmap

  • Covering-type k-violation linear programに対する近似アルゴリズム

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    日本オペレーションズ・リサーチ学会春季研究発表会  2018.3 

     More details

    Event date: 2018.3

    researchmap

  • Generalized partial covering 0--1 integer programに対する近似アルゴリズム

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    日本オペレーションズ・リサーチ学会秋季研究発表会  2017.9 

     More details

    Event date: 2017.9

    researchmap

  • 被覆型の0-1整数計画問題に対する近似アルゴリズム

    Yotaro Takazawa

    日本オペレーションズ・リサーチ学会「最適化の基盤とフロンティア」研究部会─ 未来を担う若手研究者の集い2017  2017.5 

     More details

    Event date: 2017.5

    researchmap

  • An approximation algorithm for the partial covering 0-1 integer program

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitahara

    日本オペレーションズ・リサーチ学会研究集会「最適化:モデリングとアルゴリズム」  2017.3 

     More details

    Event date: 2017.3

    researchmap

  • Approximation algorithms for covering 0-1 integer programming problems

    Yotaro Takazawa

    日本経営工学会 学生論文発表会  2017.3 

     More details

    Event date: 2017.3

    researchmap

  • Partial covering 0-1 integer programに対する近似アルゴリズム

    Yotaro Takazawa, Shinji Mizuno, Tomonari Kitakara

    日本オペレーションズ・リサーチ学会春季研究発表会  2017.3 

     More details

    Event date: 2017.3

    researchmap

  • フォーシンググラフ付き最小化ナップサック問題に対する2-近似アルゴリズム

    Yotaro Takazawa, Shinji Mizuno

    日本オペレーションズ・リサーチ学会秋季研究発表会  2016.9 

     More details

    Event date: 2016.9

    researchmap

  • フォーシンググラフ (Forcing Graph) 付き最小化ナップサック問題に対する2-近似アルゴリズム

    Yotaro Takazawa, Shinji Mizuno

    京都大学数理解析研究所研究集会 最適化技法の最先端と今後の展開  2016.8 

     More details

    Event date: 2016.8

    researchmap

  • 1次の最大・最小の期待値に対する誤差とブレイクポイント数の保証付き区分線形近似

    高澤 陽太朗

    日本オペレーションズ・リサーチ学会春季研究発表会  2023.3 

     More details

  • カバー回数が不確実な状況下でのセットマルチカバー問題に対する近似アルゴリズム

    高澤 陽太朗

    日本オペレーションズ・リサーチ学会 2021年秋季研究発表会  2021.9 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • フードデリバリーサービスにおける従業員のシフト最適化問題に対する近似アルゴリズム

    高澤 陽太朗

    2021年度科研費シンポジウム 機械学習システムの社会実装に向けた次世代最適化技法の研究  2021.9 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

▼display all

Awards

  • 第35回学生論文賞

    2017.9   日本オペレーションズ・リサーチ学会  

    Yotaro Takazawa

     More details

  • 「最適化の基盤とフロンティア」研究部会─ 未来を担う若手研究者の集い2017 ─ 優秀発表賞

    2017.5   日本オペレーションズ・リサーチ学会  

    Yotaro Takazawa

     More details

  • 学生論文賞

    2017  

    Yotaro Takazawa

     More details

  • 第1回大会優秀賞

    2022.3   Society for Computational Social Science of Japan  

     More details

    Award type:Award from Japanese society, conference, symposium, etc. 

    researchmap

Research Projects

  • 誤差と区分数のトレードオフを事前に把握可能な区分線形近似方法の研究

    Grant number:24K17471  2024.4 - 2027.3

    日本学術振興会  科学研究費助成事業  若手研究

    高澤 陽太朗

      More details

    Grant amount:\2990000 ( Direct Cost: \2300000 、 Indirect Cost:\690000 )

    researchmap

  • フードデリバリーにおける注文のバッチサイズを動的に決定するアルゴリズムの開発

    Grant number:21K14368  2021.4 - 2024.3

    日本学術振興会  科学研究費助成事業 若手研究  若手研究

    高澤 陽太朗

      More details

    Grant amount:\2860000 ( Direct Cost: \2200000 、 Indirect Cost:\660000 )

    本年度では、以下の成果を得た。下記の結果は国内の研究集会で発表した。また、成果(A)をまとめたものは学術論文誌に掲載された。
    (A) フードデリバリーサービスにおけるシフト最適化問題に対する近似アルゴリズムの研究
    一部のフードデリバリーサービスでは、配達員をシフト制とクラウドソーシングの二つを利用して集める方式が取られている。本研究では、これらの二つの方式を併用する場合の配達員のシフトを決める問題を、シナリオベースの不確実性を考慮したセットマルチカバー問題としてモデル化した。この問題はNP-困難と呼ばれる問題クラスに属すため、最適解を効率的に求めることは難しい。また、この問題に対して、既存の解の精度保証のある近似アルゴリズムを適用する場合、解の精度がシナリオ数に応じて悪化するという課題があった。本研究ではこの問題に対して線形計画法を利用した精度保証付きの近似アルゴリズムを提案した。提案アルゴリズムは解の精度保証がシナリオに依存しないという利点を持っている。今回得られた結果は、本研究課題の注文バッチを決める最適化問題の前段階における人員配置部分に利用することができる。
    (B) Twitterを用いたフードテックに関する消費者意識の研究
    本研究課題で対象としているフードデリバリーサービスはフードテックと呼ばれる領域に分類される。フードテックは日本において強くは浸透しておらず、普及のためにはシステムの最適化といったサービスの改善はもとより、消費者側の意識の把握が重要と考えられる。本研究ではTwitterを用いてフードテック(特に代替肉)に対する消費者意識の調査を行った。結果として、代替肉に関しては道徳的価値観が消費に影響を与える可能性があることがわかった。

    researchmap

  • Next Optimization Methods for Social Implementation of Machine Learning Systems

    Grant number:19H00808  2019.4 - 2022.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    Mizuno Shinji

      More details

    Grant amount:\30420000 ( Direct Cost: \23400000 、 Indirect Cost:\7020000 )

    In order to promote the social implementation of machine learning systems, we here focused on optimization algorithms that offer their computational foundations. We expanded the problem class that can be solved with high accuracy in reasonable time by enhancing and nicely applying conic optimization techniques. We also developed efficient approximation algorithms especially for discrete optimization problems that have wide applications. On the other hand, we developed modeling methodologies such that the resulting outputs can be easily accepted in practice by users of machine learning systems, as well as efficient algorithms for them. In particular, we found that imposing users’ knowledge as a constraint in the learning stage without compromising its performance is effective in practice.

    researchmap

Teaching Experience

  • Basic Mathematics for Management B

    2023.9 Institution:Meiji University

     More details

  • Mathematics B

    2023.9 Institution:Meiji University

     More details

  • Basic Mathematics for Management A

    2023.4 Institution:Meiji University

     More details

  • Mathematics A

    2023.4 Institution:Meiji University

     More details

  • Operations Research

    2023.2 Institution:Ritsumeikan Asia Pacific University

     More details

  • Elements of Discrete Mathematics

    2020.12 - 2023.2 Institution:International Christian University

     More details

  • Seminar IIB

    2023.9 Institution:Meiji University

     More details

  • Seminar IIA

    2023.4 Institution:Meiji University

     More details

  • Basic Experiments in Chemistry

    2021.4 - 2023.3 Institution:Aoyama Gakuin University

     More details

  • Topics of Industrial and Systems Engineering

    2021.4 - 2022.3 Institution:Aoyama Gakuin University

     More details

  • Computer Programming Ⅲ

    2020.10 - 2023.3 Institution:Aoyama Gakuin University

     More details

  • Seminar on Industrial and Systems Engineering Ⅰ

    2020.4 - 2023.3 Institution:Aoyama Gakuin University

     More details

  • Workshop on Optimization/Industrial and Systems Engineering Laboratory

    2019.10 - 2023.3 Institution:Aoyama Gakuin University

     More details

  • Seminar on Industrial and Systems Engineering Ⅱ

    2019.10 - 2023.3 Institution:Aoyama Gakuin University

     More details

▼display all