Yukai Zhou


2025

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Don’t Say No: Jailbreaking LLM by Suppressing Refusal
Yukai Zhou | Jian Lou | Zhijie Huang | Zhan Qin | Sibei Yang | Wenjie Wang
Findings of the Association for Computational Linguistics: ACL 2025

Ensuring the safety alignment of Large Language Models (LLMs) is critical for generating responses consistent with human values. However, LLMs remain vulnerable to jailbreaking attacks, where carefully crafted prompts manipulate them into producing toxic content. One category of such attacks reformulates the task as an optimization problem, aiming to elicit affirmative responses from the LLM. However, these methods heavily rely on predefined objectionable behaviors, limiting their effectiveness and adaptability to diverse harmful queries. In this study, we first identify why the vanilla target loss is suboptimal and then propose enhancements to the loss objective. We introduce DSN (Don’t Say No) attack, which combines a cosine decay schedule method with refusal suppression to achieve higher success rates. Extensive experiments demonstrate that DSN outperforms baseline attacks and achieves state-of-the-art attack success rates (ASR). DSN also shows strong universality and transferability to unseen datasets and black-box models.

2024

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KnowComp at DialAM-2024: Fine-tuning Pre-trained Language Models for Dialogical Argument Mining with Inference Anchoring Theory
Yuetong Wu | Yukai Zhou | Baixuan Xu | Weiqi Wang | Yangqiu Song
Proceedings of the 11th Workshop on Argument Mining (ArgMining 2024)

In this paper, we present our framework for DialAM-2024 TaskA: Identification of Propositional Relations and TaskB: Identification of Illocutionary Relations. The goal of task A is to detect argumentative relations between propositions in an argumentative dialogue. i.e., Inference, Conflict, Rephrase while task B aims to detect illocutionary relations between locutions and argumentative propositions in a dialogue. e.g., Asserting, Agreeing, Arguing, Disagreeing. Noticing the definition of the relations are strict and professional under the context of IAT framework, we meticulously curate prompts which not only incorporate formal definition of the relations, but also exhibit the subtle differences between them. The PTLMs are then fine-tuned on the human-designed prompts to enhance its discrimination capability in classifying different theoretical relations by learning from the human instruction and the ground truth samples. After extensive experiments, a fine-tuned DeBERTa-v3-base model exhibits the best performance among all PTLMs with an F1 score of 78.90% on Task B. It is worth noticing that our framework ranks #2 in the ILO - General official leaderboard.