Haokun Chen


2025

pdf bib
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)

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.

pdf bib
SwarmAgentic: Towards Fully Automated Agentic System Generation via Swarm Intelligence
Yao Zhang | Chenyang Lin | Shijie Tang | Haokun Chen | Shijie Zhou | Yunpu Ma | Volker Tresp
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing

The rapid progress of Large Language Models has advanced agentic systems in decision-making, coordination, and task execution. Yet, existing agentic system generation frameworks lack full autonomy, missing from-scratch agent generation, self-optimizing agent functionality, and collaboration, limiting adaptability and scalability. We propose **SwarmAgentic**, the *first framework that fully automates agentic system generation, optimization, and collaboration*, constructing agents from scratch and jointly refining functionality and coordination via language-driven exploration. To enable efficient search over system-level structures, SwarmAgentic maintains a population of candidate systems and evolves them via feedback-guided updates, drawing inspiration from Particle Swarm Optimization (PSO). We evaluate our method on six real-world, open-ended, and exploratory tasks involving high-level planning, system-level coordination, and creative reasoning. Given only a task description and an objective function, SwarmAgentic outperforms all baselines, achieving a **+261.8% relative improvement** over ADAS on the TravelPlanner benchmark, highlighting the effectiveness of full automation in structurally unconstrained tasks. This framework marks a significant step toward scalable and autonomous agentic system design, bridging swarm intelligence with fully automated system multi-agent generation.

pdf bib
Soft Token Attacks Cannot Reliably Audit Unlearning in Large Language Models
Haokun Chen | Sebastian Szyller | Weilin Xu | Nageen Himayat
Findings of the Association for Computational Linguistics: EMNLP 2025

Large language models (LLMs) are trained using massive datasets.However, these datasets often contain undesirable content, e.g., harmful texts, personal information, and copyrighted material.To address this, machine unlearning aims to remove information from trained models.Recent work has shown that soft token attacks () can successfully extract unlearned information from LLMs.In this work, we show that s can be an inadequate tool for auditing unlearning.Using common unlearning benchmarks, i.e., Who Is Harry Potter? and TOFU, we demonstrate that, in a strong auditor setting, such attacks can elicit any information from the LLM, regardless of (1) the deployed unlearning algorithm, and (2) whether the queried content was originally present in the training corpus.Also, we show that with just a few soft tokens (1-10) can elicit random strings over 400-characters long.Thus showing that s must be used carefully to effectively audit unlearning.Example code can be found at https://github.com/IntelLabs/LLMart/tree/main/examples/unlearning