Lujia Bai

I obtain my Ph.d. from Department of Statistics and Data Science at Tsinghua University, Beijing, China, advised by Prof. Weichi Wu . In 2020, I obtained my B.Sc. in the School of Statistics and Management, Shanghai University of Finance and Economics.

I am broadly interested in data with complex structure and non-stationary dynamics. My current research focuses on non-stationary time series, time-varying network, functional time series and long-range dependence. I speak Chinese, English and German as well as a little Spanish.

Email

profile photo
News

  • 2024-06: I have received 2024 ICSA Junior Researcher Award with the work entitled "Time-varying correlation network analysis of non-stationary multivariate time series with complex trends".

  • 2024-05: I have received the Best Poster Award of 2024 Peking-Tsinghua Joint Statistics Colloqium Forum.

  • 2024-04: I have received 2024 IMS Hannan Graduate Student Travel Award.

  • 2024-03: I have received Young Researcher Scholarship for Bernoulli-IMS World Congress.

  • 2024-03: My Contributed Session on Long Memory detection has been accepted by Bernoulli-IMS World Congress. See you in August in Germany!

  • 2024-02: Our paper "Difference-based covariance matrix estimate in time series nonparametric regression with applications to specification tests " has been accepted by Biometrika.

  • 2023-12: I have been admitted to the "Future Professor Programm" from Tsinghua University.

  • 2023-12: I will chair and give a talk in the session "Recent development on statistical analysis of complex dependent data" in CMStatistics 2023 in Berlin.
  • 2023-11: My package 'mlrv' is available on R CRAN .
  • 2023-11: I have won the First Prize of Comprehensive Scholarship of Tsinghua University.
  • 2023-09: Our paper "UniPC: A Unified Predictor-Corrector Framework for Fast Sampling of Diffusion Models" is accepted by NeurIPS 2023 .
  • 2023-09: Our paper "Detecting long-range dependence for time-varying linear models" is accepted by Bernoulli .
  • 2023-02: I am visiting Prof. Holger Dette at Ruhr University of Bochum.
  • dise Detecting long-range dependence for time-varying linear models
    Lujia Bai*, Weichi Wu
    Bernoulli, accepted
    [arXiv] [Code]

    We consider the problem of testing for long-range dependence in time-varying coefficient regression models, where the covariates and errors are locally stationary, allowing complex temporal dynamics and heteroscedasticity. We develop KPSS, R/S, V/S, and K/S-type statistics based on the nonparametric residuals.

    dise Time-varying correlation network analysis of non-stationary multivariate time series with complex trends
    Lujia Bai*, Weichi Wu
    preprint
    [arXiv]

    This paper proposes a flexible framework for inferring large-scale time-varying and time-lagged correlation networks from multivariate or high-dimensional non-stationary time series with piecewise smooth trends.

    dise Difference-based covariance matrix estimate in time series nonparametric regression with applications to specification tests
    Lujia Bai*, Weichi Wu
    Biometrika, accepted
    [arXiv] [Code]

    We propose a novel difference-based and debiased long-run covariance matrix estimator for functional linear models with time-varying regression coefficients, allowing time series non-stationarity, long-range dependence, state-heteroscedasticity and their mixtures. We apply the new estimator to existing tests, overcoming the notorious non-monotonic power phenomena and improving the performance via the residual free formula.

    dise UniPC: A Unified Predictor-Corrector Framework for Fast Sampling of Diffusion Models
    Lujia Bai*, Wenliang Zhao*, Yongming Rao, Jie Zhou , Jiwen Lu
    NeurIPS 2023
    [arXiv] [Code] [Project Page]

    UniPC is a training-free framework designed for the fast sampling of diffusion models, which consists of a corrector (UniC) and a predictor (UniP) that share a unified analytical form and support arbitrary orders.

    Honors and Awards

  • 2023 The First Prize of Comprehensive Scholarship of Tsinghua University
  • 2022 Comprehensive Scholarship of Tsinghua University
  • 2021 Comprehensive Scholarship of Tsinghua University
  • 2019 Top Ten Female College Students in Shanghai, Shanghai University of Finance and Economics
  • 2018 China Merchants Bank Scholarship, Shanghai University of Finance and Economics
  • 2017 National Scholarship, Shanghai University of Finance and Economics
  • Conferences and Workshops

  • Substitute talk in the session of change point detection. On 2024 International Conference Frontiers of Data Science, Hangzhou, Zhejiang Province, on July 2024.
  • Invited talk. On ICSA 2024 China Conference, Wuhan, Hubei Province, on June 2024.
  • 5-minute talk as a poster award winner. On 2024 Peking-Tsinghua Joint Statistics Colloqium, Beijing, on May 2024.
  • Statistical Analysis of Networks, in Coventry, UK, on September 2023.
  • Discrete Random Structures, in Lausanne, Swizerland, on August 2023.
  • Data Science and Dependence 2023 Conference, in Heidelberg, Germany, on July 2023.
  • 16th German Probability and Statistics Days, in Essen, Germany, on March 2023.
  • Invited talk. On CMStatistics 2022.
  • Best Paper Award. The 2021 International Workshop on Statistical Theory and Related Fields.
  • Invited talk. On 2021 Xiamen University Symposium on Modern Statistics.
  • Invited talk. On 2021 ICSA Applied Statistics Symposium in the session structural inference of time series data.
  • Teaching Assistants

  • 2020 Fall, Elementary Probability Theory, Tsinghua University.
  • 2021 Spring and 2024 Spring, Financial Statistics, Tsinghua University.
  • 2021 Fall, Advanced Mathematical Statistics I, Tsinghua University.
  • 2022 Spring, Applied Time Series Analysis, Tsinghua University.
  • Academic Services

  • Journal Reviewer STAT

  • Website Template


    © Lujia Bai | Last updated: July 9, 2024