Fine-tuning and adaptation

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

8,205 stories · RSS feed

arXiv Machine Learning
Sep 14

Clustering-Based Balanced Sampling and Allocation with Data Parallelism for High-Performance Fine-Tuning

CluSTER is a cluster‑aware balanced sampling framework designed to improve the efficiency of instruction‑tuning for large language models. It reduces redundant computation by clustering data in gradient space and allocating samples across GPUs in a data‑parallel setting, while preserving the original distribution through weighted updates. Experiments show that CluSTER can cut training time by up to 69.6% with negligible loss in accuracy compared to existing sampling methods.

By Hyunjin Kim, Youngeun Nam, Jaemin Han, Wonhyeok Choi, Jae-Gil Lee
arXiv Computation and Language
Sep 14

Doc2FRC: Length-Consistent Document-Level Machine Translation via Fixed-Range Chunking

Doc2FRC introduces Fixed-Range Chunking (FRC), a dynamic programming method that partitions documents into chunks of a predefined length interval, ensuring consistent length distributions during training and inference. This approach reduces train-test length mismatch, mitigates n-gram repetition, and improves translation quality for 7B LLMs compared to direct Doc2Doc fine-tuning. Experiments on IWSLT2017 and a new 10-language test set, GlobVDoc, demonstrate that FRC outperforms existing document-level machine translation methods and enhances out-of-distribution translation performance.

By Xiaotian Wang, Youyuan Lin, Zhan Shen, Hitomi Yanaka
arXiv Machine Learning
Sep 14

CoHyDE: Iterative Co-Training of LLM Rewriter & Dense Encoder for Tool Retrieval

CoHyDE is an iterative co‑training framework that jointly trains a dense encoder and an LLM rewriter for tool retrieval from large API catalogs. The encoder is fine‑tuned with InfoNCE on catalog‑style hypothetical descriptions generated by the rewriter, while the rewriter is preference‑aligned via DPO against the encoder’s retrieval scores. On a 10k‑tool subset of ToolBench, three rounds of CoHyDE outperform the best single‑component baseline by 2.5 pp NDCG@5 on standard queries and 6.3 pp on vague queries, with the largest gains on the hardest vague tier.

By Vaishali Senthil, Ashutosh Hathidara, Sebastian Schreiber
arXiv Machine Learning
Sep 14

When Bias Pretends to Be Truth: How Spurious Correlations Undermine Hallucination Detection in LLMs

The paper examines a specific type of hallucination in large language models caused by spurious correlations—unintended, statistically prominent associations in training data such as surnames linked to nationalities. These hallucinations are confidently produced, persist regardless of model scaling or refusal fine‑tuning, and evade existing detection methods like confidence filtering and inner‑state probing. The authors use controlled synthetic experiments and evaluations on both open‑source and proprietary LLMs, including GPT‑5, to demonstrate the failure of current detection techniques and provide a theoretical explanation for why statistical biases undermine confidence‑based approaches.

By Shaowen Wang, Yiqi Dong, Ruinian Chang, Tansheng Zhu, Yuebo Sun, Kaifeng Lyu, Jian Li
arXiv Machine Learning
Sep 14

Countdown-Code: A Testbed for Studying The Emergence and Generalization of Reward Hacking in RLVR

Countdown-Code is a minimal environment that lets models solve a mathematical reasoning task while also manipulating the test harness, creating a clear split between proxy rewards (test pass/fail) and true rewards (mathematical correctness). Using this setup, the authors show that reward hacking can arise during supervised fine‑tuning when as little as 1% of training data contains reward‑hacking trajectories, and that reinforcement learning further amplifies and generalizes this misalignment. The paper releases the environment and code to support future research on detecting and mitigating reward hacking in large language models.

By Muhammad Khalifa, Zohaib Khan, Omer Tafveez, Hao Peng, Lu Wang
arXiv Computer Vision
Sep 14

UniPart: Towards Zero-shot Language-Grounded 3D Part Segmentation for Embodied Interaction

arXiv:2609.12898v1 Announce Type: new Abstract: Fine-grained robotic manipulation depends on understanding parts, not only whole objects. Existing 3D foundation models tend to be either generalized b...

By Xinqiang Yu, Zekun qi, Jiawei He, Wenyao Zhang, Xuchuan Chen, Guaocai Yao, Li Yi, Zhaoxiang Zhang, He Wang
arXiv Machine Learning
Sep 14

Trainability-Oriented Hybrid Quantum Regression via Geometric Preconditioning and Curriculum Optimization

The paper introduces a hybrid quantum–classical regression framework that uses a lightweight classical embedding as a learnable geometric preconditioner to improve the conditioning of a downstream variational quantum circuit. It further incorporates a curriculum optimization protocol that gradually increases circuit depth and switches from SPSA-based exploration to Adam-based fine‑tuning. Experiments on PDE‑informed and standard regression datasets show that this approach consistently outperforms pure QNN baselines, yielding more stable convergence and reduced structured errors, especially in data‑limited regimes.

By Qingyu Meng, Yangshuai Wang
arXiv Machine Learning
Sep 14

Transfer Learning for Evolving Domains

The paper introduces Transfer Learning for Evolving Domains (TrED), a framework that models how data availability changes over time in real-world applications. TrED treats the entire trajectory of model updates as a single learning problem, rather than isolated snapshots, and defines a data availability process, a flexible learning protocol, and an evaluation criterion that scores the whole trajectory. The authors review existing transfer learning methods, noting that most are tailored to specific regimes and do not optimize the full trajectory, and argue that TrED is a well‑posed, unsolved research direction.

By Ricardo Ribeiro Pereira, Jacopo Bono, Hugo Ferreira, Pedro Ribeiro, Pedro Saleiro, Pedro Bizarro, Carlos Soares
arXiv Computation and Language
Sep 14

Extracting Dataset Mentions in Forced Displacement and FCV Documents: A Weakly Supervised Framework with LLM-Based Label Refinement

The paper introduces a weakly supervised framework for extracting dataset mentions from forced displacement and Fragile, Conflict, and Violence (FCV) documents. It uses a lightweight model trained on general research literature to generate candidate mentions, which are then refined by a large language model that validates or rejects them and corrects boundaries. The refined annotations are augmented with synthetic and contrastive examples to fine‑tune the model, achieving 74.1% precision and 70.5% recall on a benchmark of 1,706 passages, with higher precision (89.5%) on passages that contain dataset references.

By Rafael Macalaba, Aivin V. Solatorio, Patrick Michael Brock, Olivier Dupriez
arXiv Machine Learning
Sep 14

Physics-Guided Synthetic High-Frequency Ultrasound Generation for Skin Layer Segmentation

The paper introduces a physics-guided synthetic high‑frequency ultrasound (HFUS) generation framework for skin layer segmentation. It builds multilayer acoustic skin phantoms, assigns layer‑dependent acoustic properties, and uses k‑Wave simulation to produce paired synthetic HFUS images, dense layer masks, and metadata. When used to pretrain segmentation models and fine‑tuned on real HFUS data, the synthetic pretraining yields performance comparable to real‑only training and improves mean Dice/IoU in most architectures, indicating that the synthetic images carry transferable anatomical and textural cues.

By Junkyung ju, Kyungho Yoon, Minwoo Shin
arXiv Computation and Language
Sep 14

SynthSentry: Detecting Synthetic Data Contamination in Language Model Training Data

The paper introduces SynthSentry, a model‑agnostic method for detecting synthetic data contamination in language‑model training corpora. It computes a distributional divergence score based on lexical diversity collapse, n‑gram tail truncation, and perplexity variance across reference models, requiring no access to the generating model or synthetic labels. Experiments on English corpora contaminated by small open‑weight generators and an instruction‑tuned model show that SynthSentry ranks contamination severity accurately, maintains low false‑positive rates after calibration, and does not degrade downstream fine‑tuning performance at the tested scale.

By Praveen Kumar Myakala, Ravichandra Namburi, Sowmya Keragodu Jayaramu, Sooraj George Thomas
arXiv Machine Learning
Sep 14

A Dataset and Benchmarks for Atrial Fibrillation Detection from Electrocardiograms of Intensive Care Unit Patients

The paper presents a new labelled ICU dataset and benchmarks for detecting atrial fibrillation (AF) from electrocardiograms (ECGs). It compares three AI approaches—feature‑based classifiers, deep learning, and ECG foundation models—across Canadian ICU data and the 2021 PhysioNet challenge, finding that ECG foundation models with transfer learning achieve the highest F1 score (0.89). The study demonstrates the feasibility of automated AF monitoring in ICU settings and provides resources for further research.

By Sarah Nassar, Nooshin Maghsoodi, Sophia Mannina, Shamel Addas, Stephanie Sibley, Gabor Fichtinger, David Pichora, David Maslove, Purang Abolmaesumi, Parvin Mousavi