Reinforcement learning

Policy optimisation, reward modelling and RLHF — how models are trained by feedback rather than by labels.

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arXiv Computation and Language
Sep 10

AgenticGen: Reward-Guided Agentic Video Generation for Advertising

AgenticGen is a reward‑guided framework for generating advertising videos that splits the task into strategy selection and draft generation, allowing online business feedback to supervise each stage. It learns performance‑based rewards from accumulated online metrics and rubric‑based rewards aligned with human quality standards, then applies DPO and GRPO to refine policies. Offline tests confirm the reward models, and online A/B tests on TikTok show significant gains in CTR, CVR, and advertising value over a baseline.

By Xingyuan Bu, Chengru Song, Hao Zhou, Tao Zhou, Dong Li, Wei Li, Shilong Li, Hao Shi, Yongxin Guo, Donghao Zhou, Qiangpeng Yang, Shilei Wen
arXiv Machine Learning
Sep 10

Quantum Hierarchical Reinforcement Learning via Variational Quantum Circuits

The paper investigates the use of variational quantum circuits (VQCs) in hierarchical reinforcement learning (HRL). It shows that a hybrid HRL agent incorporating a quantum feature extractor can outperform classical baselines with fewer parameters, but using VQCs for option-value estimation hampers learning. The study also explores how different quantum circuit designs influence performance and proposes design principles for efficient hybrid HRL agents.

By Yu-Ting Lee, Samuel Yen-Chi Chen, Fu-Chieh Chang
arXiv AI
Sep 10

Beyond Single-Negative Preference: Multi-Negative DPO for LLM-Centric Historical Entity Linking

The paper introduces Multi-Negative Direct Preference Optimisation (MDPO), a pairwise objective that compares the correct entity with all valid rejected candidates for each mention, extending the single-negative approach used in prior work. MDPO retains the Bradley‑Terry formulation of Direct Preference Optimisation while leveraging the full candidate set through masked, length‑normalised sequence scores. Experiments on French, German, English, Swedish, and Finnish historical newspaper datasets (hipe‑2020 and newseye) show that MDPO outperforms both supervised fine‑tuning and single‑negative DPO, especially for NIL mentions, semantic ambiguity, OCR noise, and historically challenging names, and highlight candidate retrieval as a key bottleneck.

By Tien Nam Nguyen, Emanuela Boros, Ahmed Hamdi, Adam Jatowt, Micka\"el Coustaty, Antoine Doucet
arXiv AI
Sep 10

Learning to Focus: CSI-Free Hierarchical MARL for Reconfigurable Reflectors

The paper proposes a CSI‑free hierarchical multi‑agent reinforcement learning framework for controlling reconfigurable reflective surfaces in millimeter‑wave networks. By replacing per‑element channel estimation with user localization data, the system uses a two‑tier neural architecture: a high‑level controller for discrete user‑to‑reflector assignments and low‑level controllers that optimize continuous focal points via MAPPO under a CTDE scheme. Deterministic ray‑tracing tests show RSSI gains of up to 7.79 dB over centralized PPO baselines and robust performance with sub‑meter localization errors for multiple users and reflector arrays.

By Hieu Le, Mostafa Ibrahim, Oguz Bedir, Jian Tao, Sabit Ekin
arXiv AI
Sep 10

KTO: Model Alignment as Prospect Theoretic Optimization

The paper introduces KTO, a new loss function that aligns large language models with human preferences by directly maximizing a prospect-theoretic utility function rather than log-likelihood of preferences. It builds on the idea that existing alignment objectives implicitly use human-aware losses (HALOs) that reflect biases such as loss aversion. KTO achieves performance comparable to or better than preference-based methods across 1B to 30B parameter models while only requiring a binary desirability signal, and it highlights that no single HALO is universally best, emphasizing the importance of choosing the right inductive biases for a given setting.

By Kawin Ethayarajh, Winnie Xu, Niklas Muennighoff, Dan Jurafsky, Douwe Kiela
arXiv AI
Sep 10

Boosting LLM Reasoning via Human-Inspired Reward Shaping

The paper introduces T2T (Thickening-to-Thinning), a dynamic reward framework for large language models that mimics human learning by separating exploration and consolidation phases. During incorrect attempts, T2T encourages exploration to broaden the search space, while after correct solutions it applies length penalties to promote concise reasoning. Experiments on mathematical benchmarks across five mainstream LLMs show that T2T outperforms standard GRPO and recent baselines, improving overall reasoning performance.

By Wenze Lin, Zhen Yang, Xitai Jiang, Xiaoteng Ma, Gao Huang