Yujun Wang
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2026
PrivacyEvalClaw: A Tool-Augmented Deliberative Agent for Auditing Privacy Leakage in LLM Jailbreak Responses
Krishna Kanth Nakka | Yujun Wang | Shijie Zhou | Tu Nguyen | Gabriele Gelardi | Xuebing Zhou
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Krishna Kanth Nakka | Yujun Wang | Shijie Zhou | Tu Nguyen | Gabriele Gelardi | Xuebing Zhou
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Privacy auditing of large language models (LLMs) increasingly relies on advanced jailbreak attacks to uncover unintended disclosures of personal information; the reliability of such audits, however, hinges on evaluators that can accurately determine whether a response constitutes privacy leakage. This evaluation remains challenging because disclosures may be indirect, contextual, partial, or obfuscated, and different evaluators can interpret the same response differently. We conduct a systematic study of guard models and LLM-as-Judges and find substantial disagreement among evaluators, particularly in ambiguous cases that require additional evidence or targeted analysis to resolve. Motivated by these findings, we introduce PrivacyEvalClaw, a training-free deliberative agent for evaluating privacy leakage in LLM jailbreak responses. Rather than relying on isolated single-pass judgments, PrivacyEvalClaw treats evaluators and analysis modules as tools, adaptively gathers evidence, investigates uncertain disclosures, and reconciles conflicting signals before producing a final judgment. Our primary experiments use pairwise LLM-as-Judge evaluation of complete trajectories, showing that PrivacyEvalClaw achieves favorable win rates against competing baselines across outcome, process, and overall quality, while also producing explicit reasoning traces that make the evaluation process more transparent and auditable.
MemWM: Memory-Augmented Text-Based World Model
Yujun Wang | Tao Zhang | Jinhe Bi | Aniri | Wenxuan Ye | Boliang Liu | Sikuan Yan | Shuning Wang | Xuebing Zhou | Soren Pirk | Hinrich Schuetze | Yunpu Ma
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Yujun Wang | Tao Zhang | Jinhe Bi | Aniri | Wenxuan Ye | Boliang Liu | Sikuan Yan | Shuning Wang | Xuebing Zhou | Soren Pirk | Hinrich Schuetze | Yunpu Ma
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
World models are increasingly used to support planning in agents by predicting how environment states evolve in response to agent actions. Yet fluent next-state predictions can still omit task-critical facts, corrupt product attributes, or apply incorrect transition rules. To address such systematic prediction errors, we introduce MemWM, a memory-augmented text-based world model. MemWM uses world memory, a curated memory bank of transition rules, state caches, and hard-to-predict facts, to condition next-state imagination. We evaluate factual state preservation with Structured State Fidelity (SSF), which scores predicted states through benchmark-specific facts and fields. Compared with SFT, memory-augmented training improves SSF by up to 206.3%. In the full planning setting, we keep the policy model frozen and provide policy-side world skill: retrieved task-level skills and step-wise corrective guidance for action selection. Across ALFWorld, WebShop, and ScienceWorld, memory-augmented agents improve downstream success over an SFT-trained world-model agent, with up to a 65.4% relative gain. Sensitivity analyses further show that retrieved memory improves task success and efficiency under different memory and action-budget settings.
2025
LLaVA Steering: Visual Instruction Tuning with 500x Fewer Parameters through Modality Linear Representation-Steering
Jinhe Bi | Yujun Wang | Haokun Chen | Xun Xiao | Artur Hecker | Volker Tresp | Yunpu Ma
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Jinhe Bi | Yujun Wang | Haokun Chen | Xun Xiao | Artur Hecker | Volker Tresp | Yunpu Ma
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Multimodal Large Language Models (MLLMs) enhance visual tasks by integrating visual representations into large language models (LLMs). The textual modality, inherited from LLMs, enables instruction following and in-context learning, while the visual modality boosts downstream task performance through rich semantic content, spatial information, and grounding capabilities. These modalities work synergistically across various visual tasks. Our research reveals a persistent imbalance between these modalities, with text often dominating output generation during visual instruction tuning, regardless of using full or parameter-efficient fine-tuning (PEFT). We found that re-balancing these modalities can significantly reduce trainable parameters, inspiring further optimization of visual instruction tuning. To this end, we introduce Modality Linear Representation-Steering (MoReS), which re-balances intrinsic modalities by steering visual representations through linear transformations in the visual subspace across each model layer. We validated our approach by developing LLaVA Steering, a suite of models using MoReS. Results show that LLaVA Steering requires, on average, 500 times fewer trainable parameters than LoRA while maintaining comparable performance across three visual benchmarks and eight visual question-answering tasks. Finally, we introduce the LLaVA Steering Factory, a platform that enables rapid customization of MLLMs with a component-based architecture, seamlessly integrating state-of-the-art models and evaluating intrinsic modality imbalance. This open-source project facilitates a deeper understanding of MLLMs within the research community.