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Amir Houmansadr

9 accepted papers

2026

Bias Similarity Measurement: A Black-Box Audit of Fairness Across LLMs

ICLR 2026poster

Large Language Models (LLMs) reproduce social biases, yet prevailing evaluations score models in isolation, obscuring how biases persist across families and releases. We introduce Bias Similarity Measurement (BSM), which treats fairness as a relational property between models, unifying scalar, distr…

Cited by 2SourcecodeScholar
2026

Forget to Know, Remember to Use: Context-Aware Unlearning for Large Language Models

ICML 2026poster

Large language models can memorize information that must be removed--ranging from copyright-sensitive content (e.g., book chapters) to personally identifiable information (e.g., income)--to ensure responsible and compliant behavior. Unlearning has emerged as an efficient alternative to full retraini…

Cited by 0SourceScholar
2026

When Anonymity Breaks: Identifying Models Behind Text-to-Image Leaderboards

CVPR 2026

Text-to-image (T2I) models are increasingly popular, producing a large share of AI-generated images online. To compare model quality, voting-based leaderboards have become the standard, relying on anonymized model outputs for fairness. In this work, we show that such anonymity can be easily broken.

Cited by 0SourceScholar
2024

OSLO: One-Shot Label-Only Membership Inference Attacks

NeurIPS 2024poster

We introduce One-Shot Label-Only (OSLO) membership inference attacks (MIAs), which accurately infer a given sample's membership in a target model's training set with high precision using just a single query, where the target model only returns the predicted hard label. This is in contrast to stat…

Cited by 1SourcePDFScholar
2024

PostMark: A Robust Blackbox Watermark for Large Language Models

EMNLP 2024main

The most effective techniques to detect LLM-generated text rely on inserting a detectable signature—or watermark—during the model’s decoding process. Most existing watermarking methods require access to the underlying LLM’s logits, which LLM API providers are loath to share due to fears of model dis…

2023

Effectively Using Public Data in Privacy Preserving Machine Learning

ICML 2023poster

Differentially private (DP) machine learning techniques are notorious for their degradation of model utility (e.g., they degrade classification accuracy). A recent line of work has demonstrated that leveraging *public data* can improve the trade-off between privacy and utility when training models w…

Cited by 19SourcePDFScholar
2023

The Perils of Learning From Unlabeled Data: Backdoor Attacks on Semi-supervised Learning

ICCV 2023poster

Semi-supervised learning (SSL) is gaining popularity as it reduces cost of machine learning (ML) by training high performance models using unlabeled data. In this paper, we reveal that the key feature of SSL, i.e., learning from (non-inspected) unlabeled data, exposes SSL to strong poisoning attacks…

Cited by 14PDFcodeScholar
2021

Membership Privacy for Machine Learning Models Through Knowledge Transfer

AAAI 2021technical

Large capacity machine learning (ML) models are prone to membership inference attacks (MIAs), which aim to infer whether the target sample is a member of the target model's training dataset. The serious privacy concerns due to the membership inference have motivated multiple defenses against MIAs, e…