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Zihan Guan

9 accepted papers

2026

Agentic Framework for Epidemiological Modeling

ICML 2026poster

Epidemic modeling is essential for public health planning, yet traditional approaches rely on fixed model classes that require manual redesign as pathogens, policies, and scenario assumptions evolve. We introduce EpiAgent, an agentic framework that automatically synthesizes, calibrates, verifies, an…

Cited by 0SourceScholar
2026

Alignment-Weighted DPO: A principled reasoning approach to improve alignment

ICLR 2026poster

Recent advances in alignment techniques such as Supervised Fine-Tuning (SFT), Reinforcement Learning from Human Feedback (RLHF), and Direct Preference Optimization (DPO) have improved the safety of large language models (LLMs). However, these LLMs remain vulnerable to jailbreak attacks that disguise…

Cited by 0SourceScholar
2025

BalancEdit: Dynamically Balancing the Generality-Locality Trade-off in Multi-modal Model Editing

ICML 2025poster

Large multi-modal models inevitably decay over time as facts update and previously learned information becomes outdated. Traditional approaches such as fine-tuning are often impractical for updating these models due to their size and complexity. Instead, direct knowledge editing within the models pr…

2025

Benign Samples Matter! Fine-tuning On Outlier Benign Samples Severely Breaks Safety

ICML 2025spotlight

Recent studies have uncovered a troubling vulnerability in the fine-tuning stage of large language models (LLMs): even fine-tuning on entirely benign datasets can lead to a significant increase in the harmfulness of LLM outputs. Building on this finding, our red teaming study takes this threat one s…

2025

Mind Control through Causal Inference: Predicting Clean Images from Poisoned Data

ICLR 2025poster

Anti-backdoor learning, aiming to train clean models directly from poisoned datasets, serves as an important defense method for backdoor attack. However, existing methods usually fail to recover backdoored samples to their original, correct labels and suffer from poor generalization to large pre-tra…

Cited by 1SourcePDFScholar
2025

No Free Lunch: Retrieval-Augmented Generation Undermines Fairness in LLMs, Even for Vigilant Users

EMNLP 2025

Retrieval-Augmented Generation (RAG) is widely adopted for its effectiveness and cost-efficiency in mitigating hallucinations and enhancing the domain-specific generation capabilities of large language models (LLMs). However, is this effectiveness and cost-efficiency truly a free lunch? In this stud

Cited by 0SourcePDFScholar
2025

UFID: A Unified Framework for Black-box Input-level Backdoor Detection on Diffusion Models

AAAI 2025technical

Diffusion models are vulnerable to backdoor attacks, where malicious attackers inject backdoors by poisoning certain training samples during the training stage. This poses a significant threat to real-world applications in the Model-as-a-Service (MaaS) scenario, where users query diffusion models th…

Cited by 0SourcePDFScholar
2024

BadSAM: Exploring Security Vulnerabilities of SAM via Backdoor Attacks (Student Abstract)

AAAI 2024technical

Image segmentation is foundational to computer vision applications, and the Segment Anything Model (SAM) has become a leading base model for these tasks. However, SAM falters in specialized downstream challenges, leading to various customized SAM models. We introduce BadSAM, a backdoor attack tailor…

2023

Black-box Backdoor Defense via Zero-shot Image Purification

NeurIPS 2023poster

Backdoor attacks inject poisoned samples into the training data, resulting in the misclassification of the poisoned input during a model's deployment. Defending against such attacks is challenging, especially for real-world black-box models where only query access is permitted. In this paper, we pro…