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Zhiqi Bu

23 accepted papers

2025

DiSK: Differentially Private Optimizer with Simplified Kalman Filter for Noise Reduction

ICLR 2025poster

Differential privacy (DP) offers a robust framework for safeguarding individual data privacy. To utilize DP in training modern machine learning models, differentially private optimizers have been widely used in recent years. A popular approach to privatize an optimizer is to clip the individual gra…

Cited by 1SourcePDFScholar
2025

LUME: LLM Unlearning with Multitask Evaluations

EMNLP 2025

Unlearning aims to remove copyrighted, sensitive, or private content from large language models (LLMs) without a full retraining. In this work, we develop a multi-task unlearning benchmark LUME that features three tasks: (1) unlearn synthetically generated creative short novels, (2) unlearn syntheti

2025

MAP: Low-compute Model Merging with Amortized Pareto Fronts via Quadratic Approximation

ICLR 2025poster

Model merging has emerged as an effective approach to combining multiple single-task models into a multitask model. This process typically involves computing a weighted average of the model parameters without additional training. Existing model-merging methods focus on improving average task accurac…

2025

Unlearning as multi-task optimization: A normalized gradient difference approach with an adaptive learning rate

NAACL 2025long

Machine unlearning has been used to remove unwanted knowledge acquired by large language models (LLMs). In this paper, we examine machine unlearning from an optimization perspective, framing it as a regularized multi-task optimization problem, where one task optimizes a forgetting objective and anot…

Cited by 6SourcePDFScholar
2024

DOPPLER: Differentially Private Optimizers with Low-pass Filter for Privacy Noise Reduction

NeurIPS 2024poster

Privacy is a growing concern in modern deep-learning systems and applications. Differentially private (DP) training prevents the leakage of sensitive information in the collected training data from the trained machine learning models. DP optimizers, including DP stochastic gradient descent (DPSGD) a…

Cited by 2SourcePDFScholar
2024

Differentially Private Bias-Term Fine-tuning of Foundation Models

ICML 2024poster

We study the problem of differentially private (DP) fine-tuning of large pre-trained models — a recent privacy-preserving approach suitable for solving downstream tasks with sensitive data. Existing work has demonstrated that high accuracy is possible under strong privacy constraint, yet requires si…

2024

Differentially Private SGD Without Clipping Bias: An Error-Feedback Approach

ICLR 2024poster

Differentially Private Stochastic Gradient Descent with Gradient Clipping (DPSGD-GC) is a powerful tool for training deep learning models using sensitive data, providing both a solid theoretical privacy guarantee and high efficiency. However, existing research has shown that DPSGD-GC only converges…

2024

Pre-training Differentially Private Models with Limited Public Data

NeurIPS 2024poster

The superior performance of large foundation models can be attributed to the use of massive amounts of high-quality data. However, such datasets often contain sensitive, private and copyrighted material that requires formal protection. While differential privacy (DP) is a prominent method used to ga…

2024

Tractable MCMC for Private Learning with Pure and Gaussian Differential Privacy

ICLR 2024poster

Posterior sampling, i.e., exponential mechanism to sample from the posterior distribution, provides $\varepsilon$-pure differential privacy (DP) guarantees and does not suffer from potentially unbounded privacy breach introduced by $(\varepsilon,\delta)$-approximate DP. In practice, however, one nee…

Cited by 6SourcePDFScholar
2023

Automatic Clipping: Differentially Private Deep Learning Made Easier and Stronger

NeurIPS 2023poster

Per-example gradient clipping is a key algorithmic step that enables practical differential private (DP) training for deep learning models. The choice of clipping threshold $R$, however, is vital for achieving high accuracy under DP. We propose an easy-to-use replacement, called automatic clipping,…

2023

Differentially Private Optimization on Large Model at Small Cost

ICML 2023poster

Differentially private (DP) optimization is the standard paradigm to learn large neural networks that are accurate and privacy-preserving. The computational cost for DP deep learning, however, is notoriously heavy due to the per-sample gradient clipping. Existing DP implementations are 2$\sim$1000$…

2022

Scalable and Efficient Training of Large Convolutional Neural Networks with Differential Privacy

NeurIPS 2022accept

Large convolutional neural networks (CNN) can be difficult to train in the differentially private (DP) regime, since the optimization algorithms require a computationally expensive operation, known as the per-sample gradient clipping. We propose an efficient and scalable implementation of this clipp…

2021

A Dynamical View on Optimization Algorithms of Overparameterized Neural Networks

AISTATS 2021poster

When equipped with efficient optimization algorithms, the over-parameterized neural networks have demonstrated high level of performance even though the loss function is non-convex and non-smooth. While many works have been focusing on understanding the loss dynamics by training neural networks with…

2021

Accuracy, Interpretability, and Differential Privacy via Explainable Boosting

ICML 2021spotlight

We show that adding differential privacy to Explainable Boosting Machines (EBMs), a recent method for training interpretable ML models, yields state-of-the-art accuracy while protecting privacy. Our experiments on multiple classification and regression datasets show that DP-EBM models suffer surpris…

2021

Fast and Memory Efficient Differentially Private-SGD via JL Projections

NeurIPS 2021poster

Differentially Private-SGD (DP-SGD) of Abadi et al. and its variations are the only known algorithms for private training of large scale neural networks. This algorithm requires computation of per-sample gradients norms which is extremely slow and memory intensive in practice. In this paper, we pres…

Cited by 48SourcePDFScholar
2019

Algorithmic Analysis and Statistical Estimation of SLOPE via Approximate Message Passing

NeurIPS 2019poster

SLOPE is a relatively new convex optimization procedure for high-dimensional linear regression via the sorted $\ell_1$ penalty: the larger the rank of the fitted coefficient, the larger the penalty. This non-separable penalty renders many existing techniques invalid or inconclusive in analyzing the…