豊泉 洋 (トヨイズミ ヒロシ)

写真a

所属

商学学術院 大学院会計研究科

職名

教授

ホームページ

http://www.f.waseda.jp/toyoizumi/

兼担 【 表示 / 非表示

  • 理工学術院   大学院基幹理工学研究科

学歴 【 表示 / 非表示

  •  
    -
    1998年

    早稲田大学   理工学研究科   物理学及び応用物理専攻  

学位 【 表示 / 非表示

  • 早稲田大学   博士(工学)

所属学協会 【 表示 / 非表示

  •  
     
     

    日本オペレーションズリサーチ学会

  •  
     
     

    電子情報通信学会

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    日本応用数理学会

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    IEEE

  •  
     
     

    INFORMS

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研究分野 【 表示 / 非表示

  • 安全工学

  • 社会システム工学

研究キーワード 【 表示 / 非表示

  • 応用確率論

論文 【 表示 / 非表示

  • Reduction of Foraging Work and Cooperative Breeding

    Hiroshi Toyoizumi, Jeremy Field

    ACTA BIOTHEORETICA   62 ( 2 ) 123 - 132  2014年06月  [査読有り]

     概要を見る

    Using simple stochastic models, we discuss how cooperative breeders, especially wasps and bees, can improve their productivity by reducing foraging work. In a harsh environment, where foraging is the main cause of mortality, such breeders achieve greater productivity by reducing their foraging effort below full capacity, and they may thrive by adopting cooperative breeding. This could prevent the population extinction of cooperative breeders under conditions where a population of lone breeders cannot be maintained.

    DOI PubMed

  • Dynamics of social queues

    Hiroshi Toyoizumi, Jeremy Field

    JOURNAL OF THEORETICAL BIOLOGY   346   16 - 22  2014年04月  [査読有り]

     概要を見る

    Queues formed by social wasps to inherit the dominant position in the nest are analyzed by using a transient quasi-birth-and-death (QBD) process. We show that the extended nest lifespan due to division of labor between queen and helpers has a big impact on nest productivity. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

    DOI PubMed

  • Direct and Indirect Control of the Initiation of Meiotic Recombination by DNA Damage Checkpoint Mechanisms in Budding Yeast

    Bilge Argunhan, Sarah Farmer, Wing-Kit Leung, Yaroslav Terentyev, Neil Humphryes, Tomomi Tsubouchi, Hiroshi Toyoizumi, Hideo Tsubouchi

    PLOS ONE   8 ( 6 ) e65875  2013年06月  [査読有り]

     概要を見る

    Meiotic recombination plays an essential role in the proper segregation of chromosomes at meiosis I in many sexually reproducing organisms. Meiotic recombination is initiated by the scheduled formation of genome-wide DNA double-strand breaks (DSBs). The timing of DSB formation is strictly controlled because unscheduled DSB formation is detrimental to genome integrity. Here, we investigated the role of DNA damage checkpoint mechanisms in the control of meiotic DSB formation using budding yeast. By using recombination defective mutants in which meiotic DSBs are not repaired, the effect of DNA damage checkpoint mutations on DSB formation was evaluated. The Tel1 (ATM) pathway mainly responds to unresected DSB ends, thus the sae2 mutant background in which DSB ends remain intact was employed. On the other hand, the Mec1 (ATR) pathway is primarily used when DSB ends are resected, thus the rad51 dmc1 double mutant background was employed in which highly resected DSBs accumulate. In order to separate the effect caused by unscheduled cell cycle progression, which is often associated with DNA damage checkpoint defects, we also employed the ndt80 mutation which permanently arrests the meiotic cell cycle at prophase I. In the absence of Tel1, DSB formation was reduced in larger chromosomes (IV, VII, II and XI) whereas no significant reduction was found in smaller chromosomes (III and VI). On the other hand, the absence of Rad17 (a critical component of the ATR pathway) lead to an increase in DSB formation (chromosomes VII and II were tested). We propose that, within prophase I, the Tel1 pathway facilitates DSB formation, especially in bigger chromosomes, while the Mec1 pathway negatively regulates DSB formation. We also identified prophase I exit, which is under the control of the DNA damage checkpoint machinery, to be a critical event associated with down-regulating meiotic DSB formation.

    DOI PubMed

  • Analyzing Meiotic DSB Interference by Combining Southern Blotting and Microarray Analysis

    H. Toyoizumi, H. Tsubouchi

    The Fifth International Conference on Bioinformatics, Biocomputational Systems and Biotechnologies (Biotechno 2013)    2013年

  • Estimating the Number of Double-Strand Breaks Formed During Meiosis from Partial Observation

    Hiroshi Toyoizumi, Hideo Tsubouchi

    JOURNAL OF COMPUTATIONAL BIOLOGY   19 ( 12 ) 1277 - 1283  2012年12月  [査読有り]

     概要を見る

    Analyzing the basic mechanism of DNA double-strand breaks (DSB) formation during meiosis is important for understanding sexual reproduction and genetic diversity. The location and amount of meiotic DSBs can be examined by using a common molecular biological technique called Southern blotting, but only a subset of the total DSBs can be observed; only DSB fragments still carrying the region recognized by a Southern blot probe are detected. With the assumption that DSB formation follows a nonhomogeneous Poisson process, we propose two estimators of the total number of DSBs on a chromosome: (1) an estimator based on the Nelson-Aalen estimator, and (2) an estimator based on a record value process. Further, we compared their asymptotic accuracy.

    DOI PubMed

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Misc 【 表示 / 非表示

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受賞 【 表示 / 非表示

  • Biothechno 2013 優秀論文賞

    2013年05月  

  • 電子情報通信学会 交換研究会 SSE研究賞

    1999年03月  

  • 電子情報通信学会 学術奨励賞

    1997年03月  

共同研究・競争的資金等の研究課題 【 表示 / 非表示

  • コンピュータウィルスの確率論的モデル化とその能動的撃退手法の性能評価の研究

    萌芽研究

  • 決定論型と確率論型モデリングの融合による新しい待ち行列評価モデルの研究

    奨励研究(A)

特定課題研究 【 表示 / 非表示

  • 集団と個体のインタラクションのある場合の意思決定理論とその実験的検証

    2019年  

     概要を見る

    本研究は、個体と集団のインタラクションのあるプロセスにおける個体の意思決定問題の解析手法として新たに提案・研究されている平均場ゲームや非線形マル コフ過程を用いた解析手法を、ネットワーク上での情報拡散、生物の集団行動、株取引の3つ実例に応用できるように改良し、実際のソーシャルメディアのデー タ、株式市場の高速取引データ、ハチなどの生物の観測データを用いて、その妥当性・応用可能性について実験・検証・改良を行った。

  • 待ち行列モデルのグループダイナミックス評価への応用とその検証実験

    2015年  

     概要を見る

    待ち行列理論やネットワーク理論を使って、自然界で実際に見られる生物の相互の関係、特に、階級構造(女王、働き蜂)などのグループダイナミックスをモデル化し、グループ全体の性能を分析する手法を考案する。さらに、階級構造や相互関係などの待ち行列の操作実験を行うことで、分析結果を実証し、グループにおける協力関係などのダイナミックスを解明する新しい手法を開発することを目的とする。また、これらの新しいグループ全体の性能評価手法を生物だけではなく、人間社会の組織等への応用も視野に含める。

  • 待ち行列モデルの生物グループダイナミックスへの応用とその検証実験

    2014年   Jeremy Field

     概要を見る

    Using simple stochastic models, we discuss how cooperative breed- ers, especially wasps and bees, can improve their productivity by reducing foraging work. In a harsh environment, where foraging is the main cause of mortality, such breeders achieve greater productivity by reducing their for- aging effort below full capacity, and they may thrive by adopting cooperative breeding. This could prevent the population extinction of cooperative breeders under conditions where a population of lone breeders cannot be maintained. 

  • 二重鎖切断の不完全情報から遺伝子混合の特性を推定する数学手法の研究

    2014年  

     概要を見る

    It is well-known that crossover formation events on a chromosome interfere with each other during meiosis, and this interference affects the distribution of genetic exchanges on a chromosome in sexual reproduction. However, due to the technical difficulties, it is unknown if meiotic double strand break (DSB) formation, the initiating event of meiotic recombination, shows interference. We discuss a method that employs probability theory of survival analysis in conjunction with: chromosome fragment distribution, detected by Southern blotting; and genome-wide DSB intensity maps, obtained by microarray analysis. We show that this method is a promising tool to analyse DSB interference.

  • 待ち行列理論による社会性動物の協調行動の分析

    2011年  

     概要を見る

    本研究では、自然界で実際に見られる協力関係のグループダイナミックスを一つのシステムとし てモデル化し、そのシステムに対して待ち行列理論を用いることにより、グループ全体の性能を分析した。特に、マレーシアに見られるhover waspが女王の座を巡って作る待ち行列に関する実際のデータを解析し、Markov chain によりモデル化し、その特性を分析した。A wide variety of animals are known to form simple hierarchical groups called social queues, where individuals inherit resources or social status in a predictable order. Queues are often age-based, so that a new individual joins the end of the queue on reaching adulthood, and must wait for older individuals to die in order to reach the front of the queue. While waiting, an individual may work for her group, in the process often risking her own survival and hence her chance of inheri- tance. Eventually, she may survive to reach the head of the queue and becomes the dominant of the group. Queueing has been particularly well-studied in hover wasps (Hymenoptera: Stenogastrinae). In hover wasp social groups, only one female lays eggs, and there is a strict, age-based queue to inherit the reproductive position. While the dominant individual (queen) concentrates on breeding, subordinate helpers risk death by foraging outside the nest, but have a slim chance of eventually inheriting dominance. Some explanations for this altruistic behavior and for the stability of social queues have been proposed and analyzed [Field et al., 2006; Kokko and Johnstone, 1999]. Since both the productivity of the nest and the chance to inherit the dominant position depend critically on group size, queueing dynamics are crucial for understanding social queues, but detailed analy- sis is lacking. Here, using hover wasps as an example, we demonstrate that some basic queueing theory[Toyoizumi, 2008] and non-homogeneous birth and death processes are useful for analyzing queueing dynamics and the population demographics of social queues. Our work leads to better understanding of how environmental conditions and strategic decision-making by individuals inter- act to produce the observed group dynamics; and in turn, how group dynamics affects individual decision-making.

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海外研究活動 【 表示 / 非表示

  • 企業ネットワークにおける協調関係の進化の理論的研究

    2010年08月
    -
    2011年07月

    アメリカ   ハーバード大学

 

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