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Nian Si

11 accepted papers

2026

A Queueing-Theoretic Framework for Stability Analysis of LLM Inference with KV Cache Memory Constraints

ICML 2026poster

The rapid adoption of large language models (LLMs) has created significant challenges for efficient inference at scale. Unlike traditional workloads, LLM inference is constrained by both computation and the memory overhead of key–value (KV) caching, which accelerates decoding but quickly exhausts GP…

Cited by 0SourceScholar
2025

Sample Complexity of Distributionally Robust Average-Reward Reinforcement Learning

NeurIPS 2025poster

Motivated by practical applications where stable long-term performance is critical—such as robotics, operations research, and healthcare—we study the problem of distributionally robust (DR) average-reward reinforcement learning. We propose two algorithms that achieve near-optimal sample complexity.…

Cited by 0SourceScholar
2025

ScoreFusion: Fusing Score-based Generative Models via Kullback–Leibler Barycenters

AISTATS 2025oral

We introduce ScoreFusion, a theoretically grounded method for fusing multiple pre-trained diffusion models that are assumed to generate from auxiliary populations. ScoreFusion is particularly useful for enhancing the generative modeling of a target population with limited observed data. Our starting…

Cited by 0SourceScholar
2025

Statistical Learning of Distributionally Robust Stochastic Control in Continuous State Spaces

AISTATS 2025oral

We explore the control of stochastic systems with potentially continuous state and action spaces, characterized by the state dynamics $X_{t+1} = f(X_t, A_t, W_t)$. Here, $X$, $A$, and $W$ represent the state, action, and exogenous random noise processes, respectively, with $f$ denoting a known funct…

Cited by 0SourceScholar
2023

A Finite Sample Complexity Bound for Distributionally Robust Q-learning

AISTATS 2023poster

We consider a reinforcement learning setting in which the deployment environment is different from the training environment. Applying a robust Markov decision processes formulation, we extend the distributionally robust Q-learning framework studied in [Liu et. al. 2022]. Further, we improve the desi…

Cited by 36SourcePDFScholar
2023

Calibration Matters: Tackling Maximization Bias in Large-scale Advertising Recommendation Systems

ICLR 2023poster

Calibration is defined as the ratio of the average predicted click rate to the true click rate. The optimization of calibration is essential to many online advertising recommendation systems because it directly affects the downstream bids in ads auctions and the amount of money charged to advertiser…

2021

Testing Group Fairness via Optimal Transport Projections

ICML 2021spotlight

We have developed a statistical testing framework to detect if a given machine learning classifier fails to satisfy a wide range of group fairness notions. Our test is a flexible, interpretable, and statistically rigorous tool for auditing whether exhibited biases are intrinsic to the algorithm or s…

Cited by 35SourcePDFScholar
2020

Distributionally Robust Policy Evaluation and Learning in Offline Contextual Bandits

ICML 2020poster

Policy learning using historical observational data is an important problem that has found widespread applications. However, existing literature rests on the crucial assumption that the future environment where the learned policy will be deployed is the same as the past environment that has generate…

Cited by 69SourcePDFScholar
2020

Quantifying the Empirical Wasserstein Distance to a Set of Measures: Beating the Curse of Dimensionality

NeurIPS 2020spotlight

We consider the problem of estimating the Wasserstein distance between the empirical measure and a set of probability measures whose expectations over a class of functions (hypothesis class) are constrained. If this class is sufficiently rich to characterize a particular distribution (e.g., all Lips…

Cited by 18SourcePDFScholar