National Science Foundation Faculty Early Career Development (CAREER) Award

Project Information

  1. Yichen Zhang (Graduated from NYU, now an assistant at Purdue University)

  2. Zhuoyi Yang (Graduated from NYU, now an Applied Research Scientist at Amazon)

  3. He Li (Graduated from NYU, now a Research Scientist at Citadel)

  4. Wenbo Jing (Ph.D. student at NYU)

  5. Quanquan Liu (Short-term Postdoc, now an adjunct professor at the University of Texas, Dallas)

  6. Mengqian Zhang (Postdoc, now a Postdoc at Yale University)

  7. Xin Wen (Ph.D. student at NYU)

Project Goal

While traditional machine learning usually deals with given static data, many online data are collected via a sequence of interactions with agents such as crowd labelers or customers. The motivating applications of the project include crowd labeling tasks (which is a powerful paradigm for utilizing human wisdom to collect data labels), sequential product recommendation, and online multi-product pricing. For all these applications, online learning and sequential decision-making are indispensable to each other. The objective of this project is to develop new sequential learning algorithms with rigorous theoretical guarantees. The developed framework will not only make fundamental technical contributions but also facilitate many important applications. For example, it will greatly improve the aggregated answers from crowd labelers with a significantly reduced cost. It can enhance the revenue of business while improving the customers’ satisfaction by providing accurate recommendations. In addition, this project also facilitates the development of new courses on machine learning for business school students, which helps bring the knowledge from data science to future business leaders, and provides training to K-12 students, with an emphasis on those from underrepresented groups.

Publications (under this award)

  1. Dynamic Pricing with Adversarially-Censored Demands
    Jianyu Xu, Yining Wang, Xi Chen, and Yu-Xiang Wang.

  2. Stochastic Linear Bandits with Latent Heterogeneity
    Elynn Chen, Xi Chen, Wenbo Jing, and Xiao Liu.

  3. Dynamic Contextual Pricing with Doubly Non-Parametric Random Utility Models
    Elynn Chen, Xi Chen, Lan Gao, and Jiayu Li.

  4. Data-Driven Knowledge Transfer in Batch Q* Learning
    Elynn Chen, Xi Chen, and Wenbo Jing.

  5. Distributed Tensor Principal Component Analysis with Data Heterogeneity
    Elynn Chen, Xi Chen, Wenbo Jing, and Yichen Zhang.
    Journal of the American Statistical Association (Theory and Methods, to appear), 2025.

  6. Utility Fairness in Contextual Dynamic Pricing with Demand Learning
    Xi Chen, David Simchi-Levi, and Yining Wang.
    Management Science (to appear), 2025.

  7. Online Statistical Inference for Stochastic Optimization via Gradient-free Kiefer-Wolfowitz Methods
    Xi Chen, Zehua Lai, He Li, and Yichen Zhang.
    Journal of the American Statistical Association (Theory and Methods, to appear), 2024.

  8. Assortment Planning for Recommendations at Checkout under Inventory Constraints
    Xi Chen, Will Ma, David Simchi-Levi, and Linwei Xin.
    Mathematics of Operations Research, 49(1), 297–325, 2024.

  9. Robust Dynamic Assortment Optimization in the Presence of Outlier Customers
    Xi Chen, Akshay Krishnamurthy, and Yining Wang.
    Operations Research, 72(3), 999–1015, 2024.

  10. Wasserstein Distributional Robustness and Regularization in Statistical Learning
    Rui Gao, Xi Chen, and Anton J. Kleywegt.
    Operations Research, 72(3), 1177–1191, 2024.

  11. Combinatorial Inference on the Optimal Assortment in Multinomial Logit Models
    Shuting Shen, Xi Chen, Ethan X. Fang, Junwei Lu.
    ACM Conference on Economics and Computation (EC), 2023.

  12. Active Learning for Contextual Search with Binary Feedbacks
    Xi Chen, Quanquan Liu, and Yining Wang.
    Management Science, 69(4), 2165–2181, 2023.

  13. Differential Privacy in Personalized Pricing with Nonparametric Demand Models
    Xi Chen, Sentao Miao, and Yining Wang.
    Operations Research, 2022.

  14. Robust Dynamic Pricing with Demand Learning in the Presence of Outlier Customers
    Xi Chen, and Yining Wang.
    Operations Research , 2022.

  15. No Weighted-Regret Learning in Adversarial Bandits with Delays
    Ilai Bistritz, Zhengyuan Zhou, Xi Chen, Nicholas Bambos, and Jose Blanchet
    Journal of Machine Learning Research, 23(139), 1–43, 2022.

  16. Privacy-Preserving Dynamic Personalized Pricing with Demand Learning
    Xi Chen, David Simchi-Levi, and Yining Wang.
    Management Science, 2022.

  17. Online Covariance Matrices Estimation of Stochastic Gradient Descent
    Wanrong Zhu, Xi Chen, and Wei Biao Wu.
    Journal of the American Statistical Association (Theory and Methods), 2021.

  18. Distributed Estimation for Principal Component Analysis: an Enlarged Eigenspace Analysis
    Xi Chen, Jason D. Lee, He Li, and Yun Yang.
    Journal of the American Statistical Association (Theory and Methods), 2021.

  19. A Statistical Learning Approach to Personalization in Revenue Management
    Xi Chen, Zachary Owen, Clark Pixton, and David Simchi-Levi.
    Management Science, 2021.

  20. Distributionally Robust Optimization with Confidence Bands for Probability Density Functions
    Xi Chen, Qihang Lin, and Guanglin Xu.
    Informs Journal on Optimization, 2021.

  21. Optimal Policy for Dynamic Assortment Planning Under Multinomial Logit Models
    Xi Chen, Yining Wang, and Yuan Zhou.
    Mathematics of Operations Research (to appear), 2021.

  22. Dynamic Assortment Optimization with Changing Contextual Information
    Xi Chen, Yining Wang, and Yuan Zhou.
    Journal of Machine Learning Research (to appear), 2021.

  23. Tight Regret Bounds for Infinite-armed Linear Contextual Bandits
    Yingkai Li, Yining Wang, Xi Chen, and Yuan Zhou.
    International Conference on Artificial Intelligence and Statistics (AISTATS), 2021.

  24. Optimal Stopping and Worker Selection in Crowdsourcing: an Adaptive Sequential Probability Ratio Test Framework
    Xiaoou Li, Yunxiao Chen, Xi Chen, Jingchen Liu, and Zhiliang Ying.
    Statistica Sinica, 31: 519–546, 2021.

  25. Thresholding Bandit Problem with Both Duels and Pulls
    Yichong Xu, Xi Chen, Aarti Singh, and Artur Dubrawski.
    In Proceedings of the International Conference on Artificial Intelligence and Statistics (AISTATS), 2020.

  26. Bayesian Decision Process for Budget-efficient Crowdsourced Clustering
    Xiaozhou Wang, Xi Chen, Qihang Lin, and Weidong Liu.
    Proceedings of the International Joint Conference on Artificial Intelligence, 2020. [Code]

  27. Revisiting Fixed Support Wasserstein Barycenter: Computational Hardness and Efficient Algorithms
    Tianyi Lin, Nhat Ho, Xi Chen, Marco Cuturi, and Michael I. Jordan.
    In Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 2020.

  28. Robust inference via multiplier bootstrap
    Xi Chen, and Wen-xin Zhou.
    Annals of Statistics, 48(3): 1665–1691 2020. [Code]

  29. On Stationary-Point Hitting Time and Ergodicity of Stochastic Gradient Langevin Dynamics
    Xi Chen, Simon S. Du, and Xin T. Tong
    Journal of Machine Learning Research , 21(68), 1–41, 2020.

  30. EXP3 Learning in Adversarial Bandits with Delayed Feedback
    Ilai Bistritz, Zhengyuan Zhou, Xi Chen, Nicholas Bambos, and Jose Blanchet.
    In Proceedings of Advances in Neural Information Processing Systems (NeurIPS), 2019.

Software

  1. Bayesian Decision-making for Crowd Clustering. [GitHub]

  2. Robust Statistical Inference Toolbox. [GitHub]

  3. Distributed Support Vector Machine Solver. [GitHub]

Editorial Appointments and Committee Services

Presentations

  1. Temple University, AIBA Workshop, 01/2025

  2. Columbia University, DRO-IEOR Seminar, 09/2024

  3. Duke University, Fuqua School of Business, 09/2024

  4. Informs Annual Conference, Arizona, 10/2023

  5. Princeton University Wilks Statistics Seminar, Princeton, 2/2023

  6. Thirty-sixth Conference on Neural Information Processing Systems, New Orleans, 12/2022

  7. Rutgers University, Rutgers Business School, 11/2022

  8. INFORMS Revenue Management and Pricing Section Conference, Chicago, 06/2022

  9. Online Seminar of Mathematical Foundations of Data Science, Jointly by Gatech, Harvard, Northwestern, PSU, Princeton, ETH, 01/2022

  10. University of Iowa, Business Analytics Thought Leaders Symposium, Tippie College of Business, 02/2021

  11. The 23rd International Conference on Artificial Intelligence and Statistics (AISTATS), virtual, 08/2020

  12. The Eleventh POMS-HK International Conference, Hong Kong, 01/2020

  13. City University of Hongkong, Hongkong, 01/2020

  14. Informs Annual Meeting, Seattle, WA, 10/2019

  15. Joint Statistical Meetings (JSM), Denver, CO, 7/2019

  16. IMS-China International Conference on Statistics and Probability, Dalian, China, 07/2019

  17. INFORMS Revenue Management and Pricing Section Conference, Stanford Graduate School of Business, 06/2019

  18. ICSA Applied Statistics Symposium, North Carolina, 06/2019

  19. Stanford University, Department of Statistics, 06/2019

  20. Annual Conference of Production and Operations Management Society (POMS), Washington D.C., 05/2019

  21. Iowa State University, Department of Statistics, 04/2019

  22. Columbia University, Department of Statistics, 03/2019

  23. University of Miami, Miami Business School, 03/2019

  24. The University of Chicago, Booth School of Business, 03/2019

Broader Impacts

The PI has developed several key algorithms (including optimal stopping for budget control in crowdsourcing, distributed inference, and comparison-based optimization models) in the first year and has developed the code for these algorithms.

The PI has integrated the research closely with the education plan. The PI has initiated a series of statistics and machine learning courses on different levels, including undergraduate, full-time MBA, part-time MBA, specialized Master's program, and Ph.D. program (see Education for more details). The PI strived hard to incorporate the research outcomes from this project into the curriculum design. For example, the PI has initiated the first graduate course in NYU Stern B-School focusing on modern machine learning and sequential learning techniques and their applications to crowdsourcing. The PI brought new educational experience to high school students via the NYU cSplash program by delivering a new tutorial Introduction to Recommender System and Crowdsourcing. The PI also lectured in the CMU Summer School of Machine Learning based on the research outcomes from this award.

Educational Material

Awards

This material is based upon work supported by the National Science Foundation under Grant No. 1845444.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Last updated: 2025-08-12