Fine-tuning and adaptation

LoRA, PEFT, instruction tuning and domain adaptation — adapting a pretrained model without paying to train one.

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arXiv Computer Vision
Oct 7

Semantic Capability Acquisition and Specialization During Vision-Language Model Fine-Tuning

The paper investigates how vision‑language models acquire and specialize semantic capabilities during fine‑tuning, proposing a trajectory‑based framework that separates acquisition, optima, and specialization phases. It introduces Structured Semantic Routing (SSR) to analyze how supervision representation affects what is learned, showing that SSR improves name‑free attribute‑profile retrieval and that different capabilities peak at different training stages. The study reveals that continued optimization can preserve target‑class retrieval while diminishing transferable semantic knowledge, highlighting a trade‑off between specialization and generalization.

By Suguru Onda, Matthew Bailey, Ryan Farrell
arXiv Computer Vision
Oct 7

The Linear Geometry of Interpretable Tokens: Jailbreaking Attacks and Defenses for Unlearned Diffusion Models

The paper investigates how diffusion models, even after fine‑tuning to unlearn harmful concepts, still retain a linear residual of those concepts in token embeddings. It introduces SubAttack, a jailbreak method that extracts this residual by learning orthogonal attack tokens composed of interpretable textual elements, and SubDefense, a plug‑and‑play defense that projects out the same subspace to suppress the residual. Experiments show SubAttack outperforms prior attacks in power and transferability, while SubDefense offers stronger robustness and better preservation of safe generation quality.

By Siyi Chen, Yimeng Zhang, Sijia Liu, Qing Qu
arXiv Machine Learning
Oct 7

Decoupling What from Where: How Should a Small GUI Grounding Model Receive the Action Type?

The paper investigates how a small grounding model for a GUI agent should receive the action type. Using Qwen2‑VL‑2B fine‑tuned with LoRA on Android, the authors compare a flat baseline with five conditioning methods—auxiliary loss, hard‑routed action word, additive learned embedding, prepended learned token, and prompt word—under matched data, compute, and decoding settings. Results show that auxiliary loss, additive embedding, and prompt word each improve hit@0.10 by five to seven points over the baseline, while hard routing and prepended token perform similarly to the baseline; however, removing a problematic off‑screen touch point class lifts the baseline by nearly seven points, after which no method outperforms it. "whyItMatters":"The study identifies effective strategies for encoding action type in small grounding models, which could improve the accuracy of GUI agents in real‑world Android applications."

By Aadi Chauhan, Arthur Ilyasov
arXiv Machine Learning
Oct 7

Calibrated Answers About Randomized Trials From a 4-Billion-Parameter Open Model: A Registered Test and a License-Clean Release

Fiorillo v0.5 is an open 4‑billion‑parameter model that reads a randomized trial article (cut to 6,144 tokens) and predicts whether an intervention significantly increased, decreased, or had no significant effect on an outcome. Fine‑tuned on 1,431 license‑clean training articles, it achieved an expected calibration error of 0.0168, log loss 0.8603 lower than the prior, and macro‑F1 of 0.9248 on a public test split of 1,218 prompts. The model’s release, licensed under Apache 2.0, met all four pre‑registered criteria on the Open Science Framework and was validated against the evaluated predictions.

By Johann Emmanuel Li
arXiv AI
Oct 7

Principles that Guide, Actions that Inform: Agent Evolution via Knowledge Abstraction

The paper introduces SAGA, a framework that enables large language model agents to evolve by abstracting experiences into reusable principles, procedures, and episodic descriptions. SAGA transforms interaction trajectories into hierarchical knowledge with explicit applicability conditions, linking them back to execution evidence. Experiments on ScienceWorld and ALFWorld show that this execution–abstraction feedback loop improves task performance, and ablation studies confirm the importance of contextual instantiation and action regulation.

By Bowen Ye, Yongchao Xu, Junkai Ma, Xiang Yin, Wenzhao Li
arXiv AI
Oct 7

JIVEAdapter: A Multi-Task Additive Low-Rank Adapter via Joint and Individual Variation Explained (JIVE)

JIVEAdapter is a multi-task additive low-rank adapter that decomposes weight updates into a shared Joint component and a per-task Individual component, inspired by Joint and Individual Variation Explained (JIVE). It penalizes Individual structures to remain near-orthogonal to the Joint, ensuring interpretable separation of shared and task-specific signals, and allocates rank adaptively between shared and individual pools. The Joint component is learned once and frozen, then reused as a prior for new tasks, achieving competitive performance on GLUE and SuperGLUE with DeBERTaV3-base without additional modules.

By Sara Abdali, Pashmina Cameron
arXiv AI
Oct 7

AMBER: Training Long-Horizon Web Agents through Append-Only Memory

The paper introduces AMBER, an append‑only memory framework for language‑model agents that interact over long horizons. AMBER lets agents jointly learn to reason, act, and write free‑form memory, guaranteeing retention by construction and enabling end‑to‑end reinforcement learning without extensive curated data. Experiments on WebArena Lite show AMBER outperforms overwrite‑based memory by 4.09 percentage points in average success and improves task completion rates in repeated runs.

By Chinmay Savadikar, Zhaoyu Zhang, Mingyu Zhao, Shuang Xie, Han Li, Tianfu Wu, Lingyun Wang