Updated on 2026/03/07

写真a

 
KOBAYASHI GENYA
 
Organization
Undergraduate School School of Commerce Professor
Title
Professor
External link

Research Interests

  • Bayesian Econometrics

  • Bayesian Statistics

Research Areas

  • Humanities & social sciences / Economic statistics

Education

  • Kobe University   Graduate School of Business Administration

    2008.4 - 2010.3

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  • Kobe University   School of Business Administration

    2004.4 - 2008.3

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  • Kobe University   Graduate School of Business Administration

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Research History

  • Meiji University   School of Commerce   Professor

    2024.4

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  • Meiji University   School of Commerce   Associate Professor

    2022.4

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  • Chiba University   Associate Professor

    2017.4 - 2022.3

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  • Chiba University   Associate Professor

    2016.10 - 2017.3

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  • Chiba University   Lecturer

    2014.4 - 2016.9

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  • The University of Tokyo   Division of Economics, Graduate School

    2013.4 - 2014.3

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Papers

  • Flexible Bayesian quantile regression for counts via generative modeling

    Yuta Yamauchi, Genya Kobayashi, Shonosuke Sugasawa

    Biometrics   81 ( 4 )   2025.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press (OUP)  

    ABSTRACT

    Count data frequently arises in biomedical applications, such as the length of hospital stay. However, their discrete nature poses significant challenges for appropriately modeling conditional quantiles, which are crucial for understanding heterogeneous effects and variability in outcomes. To solve the practical difficulty, we propose a novel general Bayesian framework for quantile regression tailored to count data. We seek the regression parameter on the conditional quantile by minimizing the expected loss with respect to the distribution of the conditional quantile of the latent continuous variable associated with the observed count response variable. By modeling the unknown conditional distribution through a Bayesian nonparametric kernel mixture for the joint distribution of the count response and covariates, we obtain the posterior distribution of the regression parameter via a simple optimization. We numerically demonstrate that the proposed method improves bias and estimation accuracy of the existing crude approaches to count quantile regression. Furthermore, we analyze the length of hospital stay for acute myocardial infarction and demonstrate that the proposed method gives more interpretable and flexible results than the existing ones.

    DOI: 10.1093/biomtc/ujaf152

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  • Bayesian factor zero-inflated Poisson model for multiple grouped count data Reviewed

    Genya Kobayashi, Yuta Yamauchi

    Journal of Statistical Computation and Simulation   2025

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

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  • Bayesian Time-Varying Distributed Lag Nonlinear Model with Application to Analyzing the Temperature and COVID-19 Case Association Reviewed

    Dongu Han, Kljae Lee, Yeonseung Chung, Genya Kobayashi, Taeryon Choi

    Journal of Applied Statistics   2025

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  • Similarity-based random partition distribution for clustering functional data Reviewed

    Tomoya Wakayama, Shonosuke Sugasawa, Genya Kobayashi

    Journal of the Royal Statistical Society: Series C   ( 1 )   2025

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  • Predicting COVID-19 hospitalisation using a mixture of Bayesian predictive syntheses Reviewed

    Genya Kobayashi, Shonosuke Sugasawa, Yuki Kawakubo, Dongu Han, Taeryon Choi

    The Annals of Applied Statistics   18 ( 4 )   2024.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Institute of Mathematical Statistics  

    DOI: 10.1214/24-aoas1941

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  • Sequential Monte Carlo ABC: an overview with application to COVID-19 data Reviewed

    Minhyeok Kim, Dongu Han, Eunyoung Ko, Genya Kobayashi, Taeryon Choi

    Journal of the Korean Statistical Society   2024

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  • Small area estimation of general finite-population parameters based on grouped data Reviewed

    Yuki Kawakubo, Genya Kobayashi

    Computational Statistics & Data Analysis   184   107741 - 107741   2023.8

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

    DOI: 10.1016/j.csda.2023.107741

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  • Robust fitting of mixture models using weighted complete estimating equations Reviewed

    Shonosuke Sugasawa, Genya Kobayashi

    Computational Statistics & Data Analysis   174   107526 - 107526   2022.10

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

    DOI: 10.1016/j.csda.2022.107526

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  • Bayesian Approach to Lorenz Curve Using Time Series Grouped Data Reviewed

    Genya Kobayashi, Yuta Yamauchi, Kazuhiko Kakamu, Yuki Kawakubo, Shonosuke Sugasawa

    Journal of Business & Economic Statistics   40 ( 2 )   897 - 912   2022.4

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    Authorship:Lead author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:Informa UK Limited  

    DOI: 10.1080/07350015.2021.1883438

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  • Flexible Bayesian quantile curve fitting with shape restrictions under the Dirichlet process mixture of the generalized asymmetric Laplace distribution Reviewed

    Genya Kobayashi, Taeyoung Roh, Jangwon Lee, Taeryon Choi

    Canadian Journal of Statistics   2020.11

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/cjs.11582

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1002/cjs.11582

  • Estimation and inference for area-wise spatial income distributions from grouped data Reviewed

    Shonosuke Sugasawa, Genya Kobayashi, Yuki Kawakubo

    Computational Statistics & Data Analysis   145   106904 - 106904   2020.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.csda.2019.106904

    Web of Science

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  • Predicting intervention effect for COVID-19 in Japan: state space modeling approach Reviewed

    Genya Kobayashi, Shonosuke Sugasawa, Hiromasa Tamae, Takayuki Ozu

    BioScience Trends   14 ( 3 )   174 - 181   2020

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

    DOI: 10.5582/bst.2020.03133

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  • Public health improvements and mortality in interwar Tokyo: a Bayesian disease mapping approach Reviewed

    Kota Ogasawara, Shinichiro Shirota, Genya Kobayashi

    Cliometrica   12 ( 1 )   1 - 31   2018.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Verlag  

    DOI: 10.1007/s11698-016-0148-3

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  • Approximate Bayesian computation for Lorenz curves from grouped data. Reviewed

    Kobayashi, G, Kakamu, K

    Computational Statistics   2018

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  • Latent mixture modeling for clustered data. Reviewed

    Suagasawa, S, Kobayashi, G, Kawakubo, Y

    Statistics and Computing   2018

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  • Bayesian Endogenous Tobit Quantile Regression Reviewed

    Genya Kobayashi

    BAYESIAN ANALYSIS   12 ( 1 )   161 - 191   2017.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1214/16-BA996

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  • Skew exponential power stochastic volatility model for analysis of skewness, non-normal tails, quantiles and expectiles Reviewed

    Genya Kobayashi

    COMPUTATIONAL STATISTICS   31 ( 1 )   49 - 88   2016.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s00180-015-0596-4

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  • Generalized multiple-point Metropolis algorithms for approximate Bayesian computation Reviewed

    Genya Kobayashi, Hideo Kozumi

    JOURNAL OF STATISTICAL COMPUTATION AND SIMULATION   85 ( 4 )   675 - 692   2015.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1080/00949655.2013.836652

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  • The impact of social workers on infant mortality in inter-war Tokyo: Bayesian dynamic panel quantile regression with endogenous variables Reviewed

    Kota Ogasawara, Genya Kobayashi

    CLIOMETRICA   9 ( 1 )   97 - 130   2015.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s11698-014-0110-1

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  • A transdimensional approximate Bayesian computation using the pseudo-marginal approach for model choice Reviewed

    Genya Kobayashi

    COMPUTATIONAL STATISTICS & DATA ANALYSIS   80   167 - 183   2014.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.csda.2014.06.025

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  • Integrated purchase model using Gaussian Copula Reviewed

    Genya Kobayashi, Kazuhiko Kakamu, Eisaku Sato, Hideo Kozumi

    Behaviormetrika   41 ( 2 )   147 - 167   2014.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.2333/bhmk.41.147

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  • Advances in approximate Baeysian computation

    Genya Kobayashi

    Kobe University   2013.3

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    Language:English   Publishing type:Doctoral thesis  

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  • Bayesian analysis of quantile regression for censored dynamic panel data Reviewed

    Genya Kobayashi, Hideo Kozumi

    COMPUTATIONAL STATISTICS   27 ( 2 )   359 - 380   2012.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s00180-011-0263-3

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  • ABCサンプラーの最近の発展について Reviewed

    小林 弦矢

    日本統計学会誌   41 ( 1 )   155 - 180   2011.9

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

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  • Gibbs sampling methods for Bayesian quantile regression Reviewed

    Hideo Kozumi, Genya Kobayashi

    JOURNAL OF STATISTICAL COMPUTATION AND SIMULATION   81 ( 11 )   1565 - 1578   2011

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1080/00949655.2010.496117

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  • Quantile Regression Estimation Using the EM Algorithm

    Kobayashi Genya, Kozumi Hideo

    Journal of economics and business administration   202 ( 1 )   1 - 11   2010.8

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    Language:Japanese   Publishing type:Research paper (bulletin of university, research institution)   Publisher:Kobe University  

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Books

  • ベイズデータ解析

    Gelman, Andrew, Carlin, John B., Stern, Hal S., Dunson, David B., Vehtari, Aki, Rubin, Donald B., 菅澤, 翔之助, 小林, 弦矢, 川久保, 友超, 栗栖, 大輔, 玉江, 大将, Nospare

    森北出版  2024.6  ( ISBN:9784627097032

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    Total pages:xxix, 847p   Language:Japanese  

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MISC

  • Age-related Commonalities and Differences Concerning the Evaluation of Tea Beverage Package Designs

    Shioko Mukai, Genya Kobayashi, Kazuhiko Kakamu

    INTERNATIONAL JOURNAL OF PSYCHOLOGY   51   200 - 201   2016.7

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    Language:English   Publishing type:Research paper, summary (international conference)  

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Presentations

  • Dynamic Bayesian regression quantile synthesis for forecasting outlook-at-risk Invited

    Genya Kobayashi

    EAC ISBA2025  2025.7 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Predicting COVID-19 hospitalisation using a mixture of Bayesian predictive syntheses Invited

    Genya Kobayashi

    EcoSta 2024  2024 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • General Bayesian quantile regression of count via generative modeling Invited

    Genya Kobayashi

    CFE-CMStatistics 2024  2024 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Bayesian factor zero-inflated Poisson model for multpie collapsed count data Invited

    2022 

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    Language:Japanese   Presentation type:Oral presentation (invited, special)  

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  • Spatio-temporal Smoothing, Interpolation and Prediction of Income Distributions based on Grouped Data Invited

    Genya Kobayashi

    XV World Conference of the Spatial Econometrics Association  2021.5 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Bayesian approach to Lorenz curve usingn time series grouped data Invited

    Genya Kobayashi

    IISA 2019 Conference  2019.12 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Bayesian Approach to Lorenz curve using time series grouped data Invited

    Genya Kobayashi

    Workshop on Bayesian Modelling of Income and Wealth  2019.9 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Estimation and inference for area-wise spatial income distributions from grouped data Invited

    Genya Kobayashi

    SAE 2019  2019.8 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Flexible Bayesian quantile curve fitting with shape restrictions based on Gaussian process and generalised asymmetric Laplace distribution International conference

    Genya Kobayashi

    ISBA Eastern Asia Chapter  2018.7 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Flexible Bayesian quantile curve fitting with shape restrictions based on Gaussian process and generalised asymmetric Laplace distribution. International conference

    Genya Kobayashi

    ISBA World Meeting  2018.6 

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    Language:English   Presentation type:Poster presentation  

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  • Small area estimation for grouped data International conference

    Genya Kobayashi

    Small Area Estimation Conference  2017.7 

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    Language:English   Presentation type:Poster presentation  

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  • Bayesian nonparametric instrumental variable regression approach to quantile inference International conference

    Genya Kobayashi

    The First Eastern Asian Meeting on Bayesian Statistics  2016.12 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Bayesian endogenous Tobit quantile regression International conference

    Genya Kobayashi

    The 9th CSDA International Conference on Computational and Financial Econometrics  2015.7 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Approximate Bayesian computation for Lorenz curves from grouped data International conference

    Genya Kobayashi

    2015 Joint Statistical Meeting  2015.7 

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    Language:English   Presentation type:Poster presentation  

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  • The impact of piped water on the mortality in inter-war Tokyo: Bayesian disease mapping approach International conference

    Genya Kobayashi

    2015 Joint Statistical Meeting  2015.7 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Skew exponential power stochastic volatility model for analysis of skewness, non-normal tails, quantiles, and expectiles International conference

    Genya Kobayashi

    The 7th CSDA International Conference on Computational and Financial Econometrics  2013.12 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Transdimensional approximate Bayesian computation for model choice International conference

    Genya Kobayashi

    he 5th CSDA International Conference on Computational and Financial Econometrics (CFE11)  2011.12 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Generalized multiple-point algorithms for approximate Bayesian computation International conference

    Genya Kobayashi

    The 4thCSDA International Conference on Computational and Financial Econometrics (CFE10)  2010.12 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Bayesian and non-Bayesian analysis of quantile regression for longitudinal data International conference

    Genya Kobayashi

    The3rd CSDA International Conference on Computational and Financial Econometrics (CFE09)  2009.10 

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  • A Gibbs sampling approach to Bayesian quantile regression International conference

    Genya Kobayashi

    Joint Meeting of 4th World Conference of the IASC and 6th Conference of the Asian Regional Section of IASC on Computational Statistics & Data Analysis,  2008.12 

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Research Projects

  • 複雑データに対するベイズモデリングの基盤創出

    Grant number:25H00546  2025.4 - 2030.3

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    菅澤 翔之助, 入江 薫, 小林 弦矢, 橋本 真太郎, 中川 智之, 粟屋 直, 村上 大輔

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    Grant amount:\45630000 ( Direct Cost: \35100000 、 Indirect Cost:\10530000 )

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  • Novel Bayesian predictive methods for social science

    Grant number:24K00244  2024.4 - 2029.3

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

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    Grant amount:\18590000 ( Direct Cost: \14300000 、 Indirect Cost:\4290000 )

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  • 大規模データに対するベイズモデリングの新展開

    Grant number:21H00699  2021.4 - 2025.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    菅澤 翔之助, 小林 弦矢, 入江 薫, 橋本 真太郎, 中川 智之

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    Grant amount:\17160000 ( Direct Cost: \13200000 、 Indirect Cost:\3960000 )

    本研究の目的は、大規模データ解析で見受けられる実用上の問題点に着目し、それらを解決する効果的なベイズモデリングの方法論の開発を目指している。今年度は具体的に以下のような研究に取り組んだ。
    (A) 外れ値に頑健なベイズモデリング: 現実のデータには外れ値が含まれることが多く、その影響で誤った統計的推測を行ってしまう危険性がある。まず、ロバストダイバージェンスと呼ばれる分布間の尺度を用いたベイズ推測の方法論を開発し、その計算アルゴリズムの開発や理論的な性質の解明を行った。また、正規データとカウントデータの場合にそれぞれ焦点を当て、外れ値に対してロバストな確率分布を開発しその理論的な性質を明らかにした。さらにマルコフ連鎖モンテカルロ法による効率的な推定アルゴリズムも開発した。
    (B) 適応的な縮小事前分布: 大規模データ内の異質な構造を適応的に捉えることが可能な縮小事前分布の方法論の開発を行った。特にカウントデータと正値データに対する縮小事前分布を新たに開発し、その理論的な性質の解明と効率的な計算アルゴリズムの開発を行った。
    (C) 空間データに対する予測統合手法: 大規模空間データを用いて解釈性と精度が高い空間予測を行うため、複数の単純なモデルによる予測を空間潜在変化係数モデルで組み合わせる枠組みを提案し、変分近似法やマルコフ連鎖モンテカルロ法による計算手法を開発した。
    (D) 状態空間モデルの効率計算アルゴリズムの開発: 高頻度で観測される時系列データに対して状態空間モデルを用いて高速にベイズ推論を実行するための効率的な計算アルゴリズムを開発した。さらに、分布にガンマ関数を含むクラスのモデルに対してギブスサンプラーを実行するためのアルゴリズムの枠組みも開発した。

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  • 大規模データに対するベイズモデリングの新展開

    Grant number:23K20592  2021.4 - 2025.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    菅澤 翔之助, 入江 薫, 橋本 真太郎, 中川 智之, 小林 弦矢

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    Grant amount:\17160000 ( Direct Cost: \13200000 、 Indirect Cost:\3960000 )

    本研究では、大規模データに対するベイズモデリングの実用上の問題点に着目し、それらを解決する効果的な方法論の開発を目指している。今年度は具体的に以下のような活動に取り組んだ。
    (A) 縮小事前分布によるモデリングの研究: 縮小事前分布の技術を応用して、大規模データ内の特殊な構造を自動的に抽出することが可能な方法論の開発を行った。特に、関数時系列データからのトレンド抽出、単調増加制約のもとでの回帰分析を行うため縮小事前分布を開発し、その理論的な性質の解明と効率的な計算アルゴリズムの開発を行った。
    (B) 異質因果効果のベイズモデリングの研究: ベイズ的予測統合と呼ばれる枠組みを用いて、複数の異質因果効果推定量をベイズ的に統合するアルゴリズムの開発を行なった。さらに、回帰不連続デザインにおける異質因果効果を安定的に推定することが可能な階層ベイズ的アプローチの開発も行なった。
    (C) ベイズ推測のための効率的な計算アルゴリズムの開発の研究: 様々な多次元モデルを推定する際に必要となる行列一般化逆ガウス分布からの乱数生成を行うギブスサンプラーを新たに開発した。また、ランダム直交行列を効率的にシミュレーションするためのアルゴリズムの開発も行なった。
    (D) その他の研究: 上記のテーマ以外にも、裾厚な誤差分布を用いた線形回帰モデルの事後分布がロバストになる理論的な条件の考察や、隣接構造を反映したノンパラメトリックベイズ手法の開発、クラスタリング構造を用いた多変量時系列予測統合手法の開発、形状制約のある関数時系列データに対する状態空間モデルの開発などを行なった。
    (E) 研究成果の発信および関連研究者とのネットワーク構築のため、ベイズモデリングに関する国内シンポジウムを主催した。

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  • Bayesian time series and spatio-temporal analysis of income and poverty

    Grant number:21K01421  2021.4 - 2024.3

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

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    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

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  • Bayesian spatio-temporal modeling of income inequality

    Grant number:20H00080  2020.4 - 2025.3

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

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    Grant amount:\35880000 ( Direct Cost: \27600000 、 Indirect Cost:\8280000 )

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  • Small Area Estimation and Its Application to Analysis of Poverty, Public Health and Disaster (SAE)

    2018.10 - 2021.3

    Genya Kobayashi

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    Authorship:Principal investigator  Grant type:Competitive

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  • 形状に制約のあるベイズ関数回帰モデルと経済データへの応用

    2018.4 - 2021.3

    日本学術振興会  科学研究費補助金若手研究 

    小林 弦矢

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  • 多様な形態のデータに対する分位点回帰モデルと内生性についてのベイズ解析

    2015.4 - 2018.3

    日本学術振興会  科学研究費補助金若手研究B 

    小林 弦矢

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    Authorship:Principal investigator  Grant type:Competitive

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  • 分位点分布に基づいた計量モデルについての研究

    2013.4 - 2014.3

    日本学術振興会  特別研究員奨励費PD 

    小林 弦矢

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    Authorship:Principal investigator  Grant type:Competitive

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  • 分位点回帰の非線形モデルの開発,推定と時系列データへの応用についての研究

    2010.4 - 2013.3

    日本学術振興会  特別研究員奨励費DC1 

    小林 弦矢

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    Authorship:Principal investigator  Grant type:Competitive

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