arXiv AI

PLUME: Parameter-Efficient Personalization of Large Language Models via Low-Rank User Modulation in Shared Subspaces

PLUME is a lightweight framework for personalizing large language models by learning a shared task-specific subspace from aggregated user data and then training only a small square matrix for each user within that subspace. The approach introduces cross-layer shared parameters and rank‑1 residual terms to reduce redundancy while preserving expressiveness. Experiments on personalized text generation benchmarks show that PLUME matches or outperforms strong baselines while cutting per‑user parameters by over 95%.

arXiv Machine Learning
Oct 5

Does Every User Need a Private LoRA? Decoupling Personalization from Per-User Adaptation

The paper investigates how to reduce the per-user adaptation burden in personalized large language models by separating reusable personalization capacity from user-specific adjustments. Through empirical studies, it shows that shared low‑rank factors can capture much of the cross‑user structure, while a tiny user code suffices for individual correction. The proposed LINEUP framework achieves state‑of‑the‑art performance on six personalized tasks while using only eight scalars per user compared to millions of private‑LoRA parameters.

By Songyuan Sui, Srikanth Malla, Chiho Choi, Joon Hee Choi
arXiv Computation and Language
Sep 3

Beyond Retrieval: Learning Compact User Representations for Scalable LLM Personalization

The paper introduces TAP-PER, a prefix‑based framework that learns compact user representations for large language model personalization. By encoding user preferences into lightweight prefix embeddings and incorporating temporal signals, TAP‑PER avoids the need for heavy per‑user adapters or prompt‑serialized histories. Experiments on six LaMP tasks show that TAP‑PER outperforms both prompt‑based and model‑based baselines while using far fewer per‑user parameters, enabling scalable personalization at large user scales.

By Heng Cao, Fan Zhang, Jian Yao, Yujie Zheng, Changlin Zhao, Lu Hao, Yuxuan Wei, Wangze Ni, Huaiyu Fu, Yuqian Sun, Xuyan Mo
arXiv AI
Sep 7

Aplaud: Adaptive Personalized Low-Rank Decomposition for User-Specific LLM

The paper introduces Aplaud, a lightweight framework that personalizes large language models for survey response prediction. Aplaud builds on LoRA by separating adaptation into a shared low‑rank basis, a compact user‑specific correction, and a rank‑one residual for finer personalization. Experiments show that Aplaud outperforms existing LoRA‑based methods in both generalization and inference efficiency while keeping per‑user parameter costs low.

By Xinyu Li, Ruoming Jin, Jianfeng Zhu, Ruixin Guo, Zhi Liu
arXiv Machine Learning
Jun 30

Synthetic Interaction Data for Scalable Personalization in Large Language Models

arXiv:2602. 12394v2 Announce Type: replace Abstract: Personalized prompting offers large opportunities for deploying large language models (LLMs) to diverse users, yet existing prompt optimization methods primarily focus on task-level optimization while largely overlooking user-specific preferences and latent constraints of individual users.

By Yuchen Ma, Yue Huang, Wenjie Wang, Xiaonan Luo, Xiangliang Zhang, Stefan Feuerriegel
arXiv AI
Sep 24

COPE: Continual Personalization of LLMs under Sparse User Feedback via User Embeddings and Self-Evaluation

COPE (Continual Optimization with Personalized embedding and self-Evaluation) is a new framework that continually personalizes large language models using learnable user embeddings and self‑evaluation to generate proxy rewards. It integrates preference capture, self‑evaluation calibration, and personalized response optimization into a single update step, allowing continuous model updates even when explicit user feedback is sparse. Experiments demonstrate that COPE outperforms both training‑free and training‑based baselines, remains complementary to Retrieval‑Augmented Prompting, and shows reliable self‑evaluation, meaningful preference patterns, stable general capabilities, and robustness to shifting preferences and alternative evaluators.

By Ruike Cao, Fugen Yao, Liang Dong, Jian Xu, Guanjun Jiang, Li Xiao
arXiv AI
Oct 16

Explaining the Roles of Experts in Mixture-of-Experts LLMs for Personalization

The paper investigates how to personalize Large Language Models by leveraging Mixture-of-Experts (MoE) architectures, which route tokens to a few specialized experts, thereby reducing polysemanticity compared to dense models. The authors adapt three open-weight MoE LLMs on a large personalization dataset, train crosscoders to learn interpretable personalized latent representations, and identify experts that encode distinct personalization features. Experiments show that personalized MoE LLMs match dense LLM performance while activating fewer parameters, exhibit lower polysemanticity, and that causal interventions on the identified experts can steer a non-personalized model toward personalized behavior.

By Sekh Mainul Islam, Pepa Atanasova, Isabelle Augenstein