Retrieval-augmented generation

Retrieval pipelines, vector search, chunking and reranking: how models are grounded in a corpus instead of their weights.

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arXiv Machine Learning
Oct 15

TopicMerge: A Divide and Conquer Approach to Topic Modeling

TopicMerge is a multi-stage pipeline that combines efficient embedding-based clustering with Large Language Model (LLM) guidance to produce high-quality topic models. The method first over-segments a corpus into fine-grained micro-clusters, then iteratively merges them using an LLM that evaluates candidate pairs based on local context. Experiments on Bills and Wiki datasets demonstrate state‑of‑the‑art clustering performance while cutting LLM calls by more than 92% compared to document‑level approaches.

By Matthew Raffel, Lizhong Chen, Sai Munikoti, Sameera Horawalavithana
arXiv Machine Learning
Oct 15

Calibration and Risk-Budgeted Decisions with System One Models

The paper investigates how large language model (LLM) workflows and agents make binary decisions—such as allowing or blocking an input—when human deferral is not possible. It proposes using System One decision scores that default to a conservative fallback in uncertain cases and control false omission risk within the subset of inputs that receive the utility‑maximizing action. Experiments on six datasets spanning moderation, safety, and reranking show that naive threshold baselines often exceed target risk, whereas a Learn‑Then‑Test approach achieves only 7.8% risk, demonstrating the limitations of probability‑like interfaces and the benefits of risk‑budgeted selection.

By Soundouss Messoudi, Youness Mansar
arXiv Machine Learning
Oct 15

Contrastive uncertainty learning for robust multi-structure segmentation in lower-pelvic MR

The paper introduces Contrastive Uncertainty Learning (CUL), a supervised framework that leverages voxel‑wise predictive uncertainty to guide representation learning for multi‑structure segmentation in lower‑pelvic MRI. Using Monte Carlo Dropout, CUL identifies uncertain voxels and shapes the embedding space so that low‑uncertainty, correctly predicted features become stable while high‑uncertainty or misclassified features are repelled, preventing feature collapse at challenging boundaries. Evaluated on 589 prostate MRI scans with a ViT‑based UperNet decoder, CUL achieves comparable Dice scores to a baseline while significantly reducing surface distance for most structures, and ablation studies confirm the necessity of both uncertainty‑guided sampling and the contrastive objective.

By Bilal Sidiqi, Yipei Wang, Wen Yan, Shaheer U. Saeed, Daniel C. Alexander, Yipeng Hu
arXiv Machine Learning
Oct 15

The COUNT: Counting N-grams Unlocks Scaling on Host Memory and Training-Free Adaptation

The paper introduces COUNT, a method that builds n‑gram embeddings without adding learned parameters by storing precomputed n‑gram counts on host memory. By weighting the language model’s own unembeddings with corpus frequencies, COUNT can be added as an extra input embedding during pretraining, improving validation loss equivalent to a 57% increase in compute for a 1B‑parameter model. Additionally, COUNT enables efficient GPU memory usage and allows domain‑specific n‑gram tables to be swapped in at inference time for training‑free adaptation.

By Ian Magnusson, Noah A. Smith, Pang Wei Koh
arXiv Machine Learning
Oct 15

Constitutive parameterized deep energy method for solid mechanics problems with random material parameters

The paper introduces the Constitutive Parameterized Deep Energy Method (CPDEM), a physics‑driven neural network that embeds stochastic material parameters directly into the strain energy density functional. By training via expected energy minimization over the parameter domain, CPDEM learns a continuous solution manifold, enabling zero‑shot, real‑time inference of displacement fields for any material parameters without retraining or dataset generation. The method is validated on linear elasticity, finite‑strain hyperelasticity, and highly nonlinear contact mechanics, marking the first purely physics‑driven deep learning approach that efficiently handles continuous multi‑parameter variations in solid mechanics.

By Zhangyong Liang, Jihong Zhu, Huanhuan Gao
arXiv Machine Learning
Oct 15

Medical Imaging Classification with Cold-Atom Reservoir Computing using Auto-Encoders and Surrogate-Driven Training

The paper presents a hybrid quantum‑classical pipeline that uses neutral‑atom reservoir computing for medical image classification, specifically binary polyp detection. It incorporates a guided auto‑encoder to reduce dimensionality and a differentiable surrogate model to bypass the gradient barrier of quantum measurements, enabling end‑to‑end backpropagation. The resulting compact latent representations are encoded as pulse detuning parameters in a Rydberg Hamiltonian, producing quantum embeddings that feed a linear classifier, and simulations show improved performance over traditional PCA or unguided auto‑encoder methods.

By Nuno Batista, Ana Morgado, Oscar Ferraz, Sagar Silva Pratapsi, Jorge Lobo, Gabriel Falcao
arXiv AI
Oct 15

Better Capturing Interactions Between Products in~Retail: Revisited Negative Sampling for~Basket Choice Modeling

The paper presents a basket‑choice model that learns embeddings to capture interactions among products, prices, and stores, using random negative sampling to handle large item sets. Experiments on synthetic data demonstrate that sampling based on the actual assortment improves performance over existing methods. The model is validated on millions of transactions from Fortenova Group, showing potential to aid category managers in retail decision‑making.

By Jules D\'esir, Vincent Auriau, Martin Mo\v{z}ina, Emmanuel Malherbe
arXiv AI
Oct 15

A Tutorial on Quantum Amplitude Embedding with Data Re-Uploading

The paper presents a tutorial on enhancing quantum amplitude embedding through data re-uploading, a technique that repeatedly encodes input data between trainable blocks to increase model expressiveness. It demonstrates that each additional upload raises the reachable polynomial order by two and provides simulation results showing significant improvements in test coefficient of determination for higher-order targets. The study offers practical guidance on selecting the number of uploads based on the polynomial order required for a given task.

By Hyojun Ahn, Joongheon Kim
arXiv AI
Oct 15

FALLNEST: Dual-Domain Dataset Condensation of Imbalanced IMU Data for Wearable Fall Detection

The paper introduces FALLNEST, a data‑centric framework that condenses large, imbalanced inertial measurement unit (IMU) datasets into tiny, class‑balanced synthetic training sets for wearable fall detection. FALLNEST builds on dual‑domain time‑series condensation, adding a fall‑specific 7‑channel input, class‑balanced K‑Means initialization, normalized gradient matching with clipping, MMD‑based embedding alignment, and multi‑view Fourier‑domain augmentation. Experiments on SisFall, KFall, and MobiFall show that a 102K‑parameter TinyCNN trained on only 32 to 146 synthetic windows (≈1% of the original data) achieves 93.5–95.8% mean accuracy and 0.89–0.98 PR‑AUC with low variance.

By Rashi Niyas P, Ritika Jain, Hitika Tiwari