Machine Learning · Cross-listed from cs.AI
WattCouncil: Context-Aware Household Energy Scenario Generation With Governed LLMs
Mohannad Takrouri, Nicolas M. Cuadrado A. and Martin Takáč
The accelerating shift toward low-carbon power systems, together with the widespread adoption of behind-the-meter technologies such as rooftop
solar and electric vehicles, is placing new operational and analytical demands on electricity grids. At the same time, smart-grid research increasingly relies on machine learning (ML), yet progress is constrained by limited access to high-resolution household energy data due to
privacy concerns, regulatory barriers, and collection costs. This work presents WattCouncil, a data-generation framework in which household electricity demand is generated by a council of Large
Language Model (LLM)-based
agents operating in specialized roles to generate, audit, and validate structured energy scenarios under explicit cultural, temporal, and physical constraints. Rather than acting as static predictors, these
agents serve as adaptive decision-makers within a governed pipeline. Motivated by studies highlighting the importance of contextual factors in energy use, our framework produces context-sensitive daily routines through a guided
reasoning process that incorporates household composition, temporal factors, and environmental conditions. We evaluate the generated profiles against the detailed CER
dataset, which contains over a year of load measurements for 4232 households together with survey-based socio-economic information. We further assess the consistency of the framework through ablation studies. Source code is available at https://github.com/Singularity-AI-Lab/wattcouncil
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Machine Learning · Cross-listed from quant-ph
MDQEC-QAS: Meta-Decoding for Quantum Error Correction with Hardware-Aware VQC Search and Confidence-Gated Recovery
Prashant Kumar Choudhary, Nouhaila Innan, Muhammad Shafique et al. (+1 more)
We propose a unified meta-decoding framework for
quantum error correction that learns syndrome-to-recovery mappings across multiple stabilizer codes and noise settings, without requiring separate decoders for each configuration. The
benchmark includes FiveQubit, Steane, Planar3x3, and Planar5x5 codes, four noise families, and five evaluation regimes: interpolation, unseen-p transfer, unseen-noise transfer, few-shot unseen-code adaptation, and few-shot held-out-size adaptation. We compare a classical Meta-MLP teacher-trained baseline with variational
quantum circuit (VQC) meta-decoders selected through hardware-aware
quantum architecture search over
qubit count,
circuit depth, and entangling
topology. The Meta-MLP achieves teacher-label accuracies of 0.9993, 0.9118, 0.9342, 0.6304, and 0.7548 across the five regimes, while the hardware-aware VQC achieves 0.9400, 0.8495, 0.8415, 0.5678, and 0.7143. However, logical-level evaluation shows that high teacher-label accuracy alone is insufficient in the most challenging Planar5x5 setting. During interpolation, the raw logical-failure ratios relative to the teacher are 12.08 and 25.91 for the Meta-MLP and VQC, respectively, whereas confidence-gated fallback reduces them to 1.71 and 1.11. These results support confidence-aware selective recovery rather than unconditional teacher replacement.
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All authors Prashant Kumar Choudhary, Nouhaila Innan, Muhammad Shafique, Rajeev Singh
Machine Learning · Cross-listed from cs.RO
Action Map Policy: Learning 3D Closed-loop Manipulation via Pixel Classification
Haojie Huang, Zhang Ye, Linfeng Zhao et al. (+7 more)
The action space poses a major challenge in
robot learning, since it is often high-dimensional, can span long time horizons, and frequently admits multi-modal optimal solutions. A good choice of action representation and loss function can help to address these concerns, but there are often trade offs. We propose Action Map Policy (AMP), which casts 3D closed-loop manipulation policy learning as a classification problem in image space. While classification has been an effective formulation in generative
language models, applying it to
robot action learning is difficult because naively discretizing high-dimensional continuous actions explodes the
token vocabulary. Our key idea is to project 3D actions onto the camera image planes and treat each pixel location as a discrete class, thus controlling dimensionality while retaining multi-modality. This method supports millimeter-level precision for high-dimensional actions without requiring a prohibitively large vocabulary, while preserving fine-grained pixel-wise visual signals. Furthermore, it can predict the entire action chunk in a single forward pass, avoiding complex noise scheduling and iterative denoising while achieving substantially faster inference than
diffusion policies. Experiments on various manipulation tasks show that AMP outperforms strong baselines, achieving higher success rates, faster inference, and enhanced spatial
reasoning.
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All authors Haojie Huang, Zhang Ye, Linfeng Zhao, Boce Hu, Mingxi Jia, Yu Qi, Ahmed Agha, Dian Wang, Robert Platt, Robin Walters
Machine Learning
On the modality gap and the contrastive loss in multi-modal representation learning
Fabian Mager, Hiba Nassar and Lars Kai Hansen
We study the modality gap in CLIP-style dual-encoder contrastive learning, where image and text
embeddings remain misaligned despite being trained in a shared space. We argue that the gap is induced by a failure of the InfoNCE formulation with independent encoders. We conduct a uni-modal experiment with two independent encoders and identical initialization conditions and find that InfoNCE actively generates a gap at low temperatures. We provide a theoretical analysis of this phenomenon and show that the modality gap is indeed a mode-failure of InfoNCE, but only at low temperatures. We propose a simple modification called xNCE, which uses intermodal as well as intra-modality negative contrastive pairs. xNCE matches
retrieval performance on MS-COCO while consistently reducing the gap even at low temperatures. Notably, xNCE improves zero-shot classification over the InfoNCE baseline across all
benchmarks, whereas high-temperature InfoNCE and regularized InfoNCE both fail to do so, demonstrating that xNCE reduces the modality gap without sacrificing the discriminative geometry needed for transfer.
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Machine Learning
Learning to Fine-tune Foundation Models under Resource Limitations
Thomas Tsouparopoulos and Iordanis Koutsopoulos
We study the problem of optimal continual fine-tuning for a pre-trained Foundation Model deployed at a resource-limited device. At each time slot, a new batch of training data arrives, and the controller is faced with two options: either use the data to fine-tune the model and incur a compute cost, or do not fine-tune the model and discard the data. After the decision, the performance of the current model is measured in terms of an application-specific performance metric such as classification accuracy. Our objective is to learn an optimal policy that determines when to fine-tune the model on a single task (e.g., sentiment analysis), under a finite compute budget. We formulate this online decision-making problem as a constrained Markov Decision Process, where the system state captures three essential aspects: (i) model's performance, (ii) computational budget, and (iii) data distribution relevance to historic data encountered up to that point. The transition to the next state is
stochastic and therefore, we propose a reinforcement learning-based method to solve this problem, namely the actor-critic
algorithm. We also consider the special case where the performance of fine-tuning for a given model can be predicted or estimated prior to decision; in this case the problem becomes a Dynamic Programming one. Experiments with a large pre-trained model on a widely-used text classification
dataset demonstrate that our method consistently outperforms fine-tuning approaches with the same compute budget by more than $4\%$ in terms of accuracy and achieves $97\%$ of full-parameter fine-tuning accuracy while requiring only $25\%$ of the fine-tuning steps.
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Machine Learning
Spectral Margins and Memory Routing in Looped Transformers
Matthias M. M. Buehlmaier
Looped
transformers apply one block of weights repeatedly. Each iteration keeps a fraction of the previous hidden state, the carry, and adds the block's output, so information can pass between iterations through either path. We study a small, LayerNorm-based variant of the Parcae architecture and ask two questions: does the iterated state settle, and does learning to remember across iterations require the carry? On stability, pre-LayerNorm makes the block less sensitive at its fixed point as the carry grows, but not enough to guarantee contraction: with a scalar carry, a perturbation can grow in a single iteration even at a locally stable fixed point. These fixed points are stable because the spectral radius of the loop's Jacobian stays below $1$; its distance from $1$, the spectral margin, narrows as the carry approaches $1$ and, at high carry, as the width grows, and some initializations do not settle within the iteration budget. On
memory, a multi-hop copy task trained at a fixed loop depth is learned as well with the carry frozen at $0.5$, $0.02$, or $0$ as with a learned carry, which changes little during training. When the depth is sampled during training, a carry of $0.5$ still trains but $0.02$ and $0$ do not. All experiments are small ($d \le 32$ for training).
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Machine Learning
Binbin Lin, Wei Chen, Yalun Li et al. (+3 more)
Self-
attention is a ubiquitous primitive in modern sequence models, yet its operator-level geometry is only partially understood. We view a
token sequence as a vector field over the
token-position graph and identify
attention as a connection walk: messages are aggregated by a nonnegative walk
matrix while being transported along each edge by a learned linear map. Within this framework, we prove that single-head
attention (SHA) is exactly a connection propagation step with constant transport, and that multi-head
attention (MHA) is exactly a single edge-dependent connection walk whose effective transport is an
attention-gated mixture of headwise transports. We further clarify the conditions under which the corresponding generator reduces to a random-walk connection
Laplacian, highlighting the roles of stochasticity, reversibility, and metric-compatible transports. Empirically, we find that trained
Transformers across scales (from 124M to 8B) and structures (encoder/decoder) exhibit
geometric structure consistent with our theory: effective
attention graphs converge to stable
geometric operators in deeper layers, learned transports self-organize into approximate scaled isometries, and both phenomena strengthen consistently with scale. Overall, the paper provides a precise connection-walk formalism that links self-
attention to classical
geometric operators, along with a set of operator-level tools for analyzing
transformer models from a
geometric perspective.
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All authors Binbin Lin, Wei Chen, Yalun Li, Wenxiao Wang, Jieping Ye, Xiaofei He
Machine Learning
tidyHEBO: Improving the Robustness of Heteroskedastic Evolutionary Bayesian Optimization
L. A. Zhukov, E. V. Shaburova and D. V. Antonets
Bayesian optimization is widely used for expensive black-box optimization problems. While methodological advances often focus on individual components, practical performance depends on how these components work together. We present tidyHEBO, a
Bayesian optimization model. tidyHEBO jointly learns output warping and Gaussian-process parameters, evaluates acquisition functions on the original objective scale, and preserves promising novel candidates throughout evolutionary search. On the Olympus
benchmark, tidyHEBO ranked first among the evaluated methods, achieving the best average ranks for typical optimization quality, worst-tail outcomes, and run-to-run variability. It also obtained results comparable to specialized optimizers on Needle-in-a-Haystack problems. On the Bayesmark
benchmark, tidyHEBO also demonstrated strong results in hyperparameter tuning. Across these
benchmarks, tidyHEBO combines strong optimization results with robustness across diverse black-box problems.
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Machine Learning · Cross-listed from cs.CV
Answer-Conditioned Chain-of-Thought Distillation for Few-Shot Industrial Vision with Small VLMs
Shubham Rao
Deploying AI-based visual inspection in manufacturing is hard because requirements change often, new defect types appear, and large labeled
datasets are rarely available. We propose answer-conditioned chain-of-thought (CoT)
distillation for rapidly adapting small
vision-
language models (VLMs) to new industrial tasks using minimal labeled data. A frontier VLM receives each training image along with its correct label and generates a justified visual explanation. A 3B-parameter model is then fine-tuned on these
reasoning-augmented examples via LoRA. By conditioning on correct answers, we ensure all training
reasoning is directed toward the correct conclusion, which is critical because frontier models score as low as 24.1% on our hardest task. We validate on four industrial classification tasks spanning three image modalities using only 18 to 30 labeled images per task. Across 4 seeds per task (32 training runs), our method outperforms direct fine-tuning on all 16 seed-task combinations, with mean improvements of +1.7 to +4.4 percentage points. A controlled equal-budget experiment confirms the improvement comes from
reasoning quality, not additional training steps. An unconditioned baseline demonstrates that with out answer-conditioning, wrong
reasoning degrades performance by 17.8 percentage points. On weld radiograph classification, the fine-tuned 3B model outperforms GPT-4.1 by 10.0pp using just 24 training images.
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Machine Learning · Cross-listed from stat.ML
Edge Cluster Expansion with Radial Rotary Attention for Interatomic Potentials
Zemin Xu, Wenbo Xie and P.Hu
In this paper, we provide a systematic investigation of SO(2) theory to machine learning interatomic potentials (MLIPs) and identify the limitations of conventional SO(2) Linear architectures relative to SO(3) Clebsch-Gordan Tensor Products (CGTP). Building on these insights, we propose direct Cartesian construction and recursive Clebsch-Gordan construction of Wigner D-
matrices and introduce two novel interaction building blocks. First, we propose the Edge Complex Product Basis based on Generalized Asymmetric Contraction, a new formulation for many-body expansion that directly constructs higher-order interactions on edges through complex-valued equivariant multiplications. Second, we introduce Radial Rotary Complex
Attention(RRA), which enhances extrapolation performance and surpasses existing
attention vector formulations. We also introduce several improvements to the Atomic Cluster Expansion module. Building on these advances, we train our models on OMat24, sAlex, and MPTrj, and introduce TECE-OAM-RRA-1.0, which achieve state-of-the-art (SOTA) performance on the Matbench Discovery.
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Machine Learning · Cross-listed from quant-ph
Learning Topological Quantum Phases from Limited Subsystems
Mehran Khosrojerdi, Sougato Bose, Alessandro Cuccoli et al. (+3 more)
Characterizing
quantum topological phases requires measuring non-local string order parameters, demanding access to the full system, which is often experimentally unfeasible. In this work, we introduce a data-efficient supervised learning framework that circumvents this limitation by recognizing
quantum phases from small subsystems. Our protocol utilizes a
quantum kernel constructed from the reduced density
matrices of these subsystems, which can be efficiently estimated experimentally. We
benchmark our framework with the classification of the phase diagrams of two
spin models on one-dimensional
lattices, namely the generalized cluster-Ising
spin-1/2 chain and the anisotropic Haldane
spin-1 chain. Remarkably, our approach achieves high accuracy in phase classification when operations are limited to as few as one to four sites, and it also generalizes to longer chains even when trained on moderate system sizes. These findings demonstrate that local reduced density
matrices preserve vital signatures of global topological phases, offering a practical route to characterize rich phase diagrams of
quantum many-body systems.
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All authors Mehran Khosrojerdi, Sougato Bose, Alessandro Cuccoli, Paola Verrucchi, Abolfazl Bayat, Leonardo Banchi
Machine Learning
Auditing Construct Overlap in Explainable Machine Learning: Evidence from Burnout-Depression Prediction Across Student Cohorts
Alireza Dehghan and Negin Ashrafi
Explainable machine learning (XML) pipelines applied to composite mental health outcomes can produce apparently-robust, cross-population-stable risk hierarchies that are largely artefacts of how the outcome was constructed. We demonstrate this using an ElasticNet pipeline applied to 886 medical students at the University of Lausanne (primary cohort, 2022), validated across 2,580 longitudinal observations at three time points and 701 non-medical students from eight faculties; all three
datasets share identical instruments. The pipeline produces a hierarchy in which trait anxiety and health satisfaction dominate wherever the outcome is measured, with Kendall $\tau = 1.0$ for the top-two positions across all five evaluation sets and consistent transfer performance ($R^2$: 0.41-0.49). Two residualization experiments, which isolate shared variance between correlated variables via regression, reveal the mechanism: when trait anxiety (STAI-T) is residualized against the co-included depression subscale (CES-D, $r = 0.72$), model $R^2$ drops from 0.41 to 0.16 and STAI-T falls from rank 1 to rank 6; when burnout subscales are residualized against CES-D, $R^2$ collapses to 0.016. Prediction intervals average 35.4 units on a 0-100 scale (2.4 outcome standard deviations), independently ruling out individual-level deployment. The residualization protocol is the paper's transferable contribution: any XAI study combining correlated predictor and outcome constructs should apply this check before interpreting apparent stability as a finding.
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Machine Learning · Cross-listed from stat.ML
Demixing Sparse Signals from Nonlinear Observations using Generalized Non-convex Regularization
Raziyeh Takbiri
We consider the recovery of a pair of sparse vectors from a limited number of nonlinear observations of their superposition: $y_i=g(\inner{\ba_i}{\bPhi\bw^\ast+\bPsi\bz^\ast})+e_i$, $i=1,\dots,m$, with $m\ll n$, incoherent orthonormal bases $\bPhi,\bPsi$, a scalar link $g$, and noise $e_i$ that may be heavy-tailed or contaminated. We propose a regularization-based framework combining a Huberized data fidelity with generalized folded-concave penalties (SCAD, MCP), and a two-block proximal alternating
algorithm with backtracking (NLD-PALM) whose whole iterate sequence provably converges to critical points under the Kurdyka–Łojasiewicz property, with local linear rates. On the statistical side we establish restricted strong convexity of the Huberized nonlinear loss through an exact sign-definite decomposition, and derive estimation error bounds of order $\sigma\sqrt{s\log(n)/m}$ that hold at every localized stationary point, an oracle rate $\sigma\sqrt{s/m}$ free of $\log n$ and shrinkage bias under a beta-min condition, and a co-equal recovery
theorem for unknown monotone links via a linear surrogate and a clipped Plan–Vershynin decoupling. The
estimator requires no knowledge of the sparsity levels, and its guarantees hold under symmetric noise with only finite variance. Experiments at $n=512$ under a frozen data-driven regularization rule show an earlier phase transition than convex $\ell_1$ demixing and greedy hard-thresholding baselines, a $35\times$ accuracy advantage over squared-loss estimation under $5\%$ gross outliers, and successful demixing of spike-plus-background signals observed through a saturating amplifier.
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Machine Learning
modelDNA: Calibrated Lineage Verification and Merge Decomposition from Sampled Weight Fingerprints
Muhammad Awais Bin Adil and Saad Aamir
The lineage graph of open-weight
language models is self-reported: Hugging Face's base_model metadata field is optional and unverified, and over 60% of Hub models document no parentage at all. Methods for detecting lineage from weights exist in the research literature, but each ships as paper code tied to one signal and one experiment; when a provenance dispute breaks, the analysis is redone by hand. This report describes modelDNA, a tool that fingerprints a model from roughly 100-300 MB of ranged HTTP reads (instead of a full 15 GB download for a 7B model), compares the fingerprint against a reference database of foundation models across four published signal families, and returns one of eight verdict classes with a calibrated probability, preferring honest abstention to confident error. On a
benchmark of 15 real Hub models with org-documented parentage, judged against 8 candidate bases (13 positives, 107 hard negatives), the system achieves AUROC 1.0, zero false positives at its reporting threshold, and 13/13 correct top-1 parent attribution. The report's second contribution is merge decomposition. Every mainstream weight-merging method is (near-)linear per tensor, and fingerprint sample positions are deterministic functions of tensor identity, so a merged model's fingerprint is the same linear combination of its parents' fingerprints. Mixture weights can therefore be recovered from fingerprints alone by sum-to-one constrained least squares. Against merges with published mergekit configurations as ground truth, the method recovers a slerp merge's layer-interpolation curves at r = 0.999 and a dare_ties merge's mixture weights to within 0.011 of the published values, without downloading any weights beyond the fingerprints. All fingerprints,
benchmarks, and the inferred lineage graph of 55 models are public and reproducible offline.
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Machine Learning
M+Adam: Low-Precision Training via Additive-Multiplicative Optimization
Xiaoyuan Liang, Sebastian Loeschcke, Mads Toftrup et al. (+1 more)
Training with quantized weights can reduce costs but often results in degraded accuracy, especially when optimization is carried out in low precision, without storing high-precision copies. We identify a key failure mode: under low precision, standard optimizers can get stuck and not make progress, especially at large weight magnitudes due to coarse mantissa resolution. To overcome this, multiplicative updates have been previously proposed, in place of additive updates in standard optimizers. While successful under extremely low precision, such as under the logarithmic number system, they suffer from failures near zero and across sign changes. The failure modes of additive and multiplicative updates are therefore complementary. To exploit this, we propose M+Adam, which combines both update types: additive steps handle sign changes and small magnitudes, while multiplicative steps ensure progress at large magnitudes when additive updates are zeroed out under rounding. We prove monotone descent for M+Adam under standard smoothness assumptions. Across LLaMA-style pretraining with 60M-1B models, 1x-8x Chinchilla budgets, and using only BF16, FP8, and FP4 master weights, M+Adam consistently improves low-precision training.
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All authors Xiaoyuan Liang, Sebastian Loeschcke, Mads Toftrup, Anima Anandkumar
Machine Learning · Cross-listed from cs.CV
End-to-End Real-Time Drone-Based Person Detection Framework Using Deep Learning
Payel Sarmah, Ayush Ranjan, Piyush Kaushik Bhattacharyya et al. (+2 more)
In recent years, Unmanned Aerial Vehicles (
UAVs) or drones have gained rapid response in terms of security, search and rescue (SAR), border surveillance, etc. Existing monitoring frameworks often struggle to maintain detection consistency when targets undergo significant scale variations due to altitude changes, leading to critical information gaps. To address this issue, this work proposes an integrated real-time detection pipeline for detecting targets through the wireless live drone
video feed. Build upon YOLOv8-nano architecture, extensive flight experiments were conducted to determine the detection performance across multiple flight altitudes. Trained on VisDrone2019
dataset, the results of YOLOv8-nano model achieves 57.4%, 41%, 44.8% and 20.3% in precision, recall, mAP and mAP50:95 respectively. While demonstrating on real environment, this analysis revealed that the
algorithm achieves near-total detection reliability at altitudes between 16 and 25 meters with the detection frame rate consistently maintained above 41 FPS and reaching a peak of 50 FPS. However, the goal of this work is to enable real-time person detection from an aerial platform via wireless transmission. This approach effectively addresses the dual challenges of identifying targets at varying scales and ensuring near-to-accurate localization during aerial observation.
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All authors Payel Sarmah, Ayush Ranjan, Piyush Kaushik Bhattacharyya, Anil Kr. Shaw, Pradip Kr. Das
Machine Learning
AutoNorm: Understanding Adaptive Normalization in Transformers through Differentiable Gating
Piyush Kaushik Bhattacharyya, Divyanshu Rai, Swastik Singh et al. (+3 more)
Normalization is a critical component for stabilizing
Transformer training, yet the choice between static strategies such as Layer Normalization (LN) and adaptive alternatives remains largely task-dependent. In this paper, we investigate a key optimization challenge in differentiable normalization gating. Our experiments show that, on relatively stationary
vision tasks, the high gradient variance introduced by Gumbel-Softmax gating can hinder convergence of the routing mechanism, causing learned gates to underperform simple random selection. In contrast, on non-stationary
language modeling and classification tasks, sustained gating diversity enables the model to learn more effective layer-wise normalization policies. Motivated by these observations, we propose AutoNorm-S (Stabilized), a training strategy that mitigates optimization instability through a gate-freezing schedule. AutoNorm-S achieves competitive or improved performance across multiple
benchmarks, outperforming adaptive normalization baselines on NLP
datasets, including PTB and SST-2, while remaining competitive on standard
vision benchmarks. These results suggest that decoupling normalization selection from optimization noise provides a practical and principled approach for adaptive normalization in
Transformer architectures.
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All authors Piyush Kaushik Bhattacharyya, Divyanshu Rai, Swastik Singh, Kumar Aakash, Ayush Ranjan, Krutika Verma
Machine Learning
Sharp Concentration Bounds for Bundle-Valued Statistics on Manifolds
Swagatam Das and Vaclav Snasel
Many
geometric statistics and
manifold learning pipelines routinely produce observations – such as tangent vectors or local frames – whose natural home is a varying family of fibers attached to different points of a base
manifold, rather than a single shared vector space. Forming empirical averages requires transporting these observations to a common reference fiber, thereby introducing
curvature- and holonomy-driven effects that are absent from classical concentration theory. We develop a non-asymptotic concentration theory for such transported empirical means, deriving finite-sample, dimension-free Hoeffding- and Bernstein-type bounds via sharp
Hilbert-space inequalities. When shortest paths to the reference point are non-unique, transport becomes path-dependent and introduces a deterministic holonomy bias; we isolate and quantify this bias through bundle
curvature and loop geometry, with sharp closed-form formulas for the tangent bundle of a round sphere. The resulting bias-variance decomposition separates the
stochastic fluctuation decaying at the classical $n^{-1/2}$ rate in sample size $n$, from a
curvature-driven error floor that no amount of additional data can eliminate; minimax lower bounds confirm both terms are unavoidable. We further establish a robust median-of-means
estimator achieving optimal rates under heavy tails and the central limit
theorem in the reference fiber. Controlled experiments on the sphere validate all theoretical predictions.
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Machine Learning · Cross-listed from stat.ML
Approximation of Analytic Functions by ReLU Neural Networks with Adjustable Depth and Width
Yanming Lai, Defeng Sun and Yang Wang
In contrast to most studies on neural network approximation theory that characterize results through a single parameter, such as the total number of network parameters, \cite{shen2020deep} pioneered the characterization of approximation rates as a joint function of the width parameter $N$ and the depth parameter $L$, thereby granting greater architectural flexibility. Existing works using the $(N,L)$-characterization focus on function classes with finite smoothness $s$, establishing a typical approximation rate of $\mathcal{O}\left(N^{-2s/d}L^{-2s/d}\right)$ with $d$ denoting the input dimension, which indicates that network depth and width play symmetric roles for these classes. In contrast, this paper establishes upper bounds for the approximation of analytic functions, which possess infinite smoothness, via ReLU networks under the $(N,L)$-characterization. Specifically, we derive approximation rates of $\mathcal{O}\left(N^{-C L^{\tau}}\right)$, where $C>0$ is some constant and $\tau>0$ is a parameter influenced by the relation between $L$ and $N$. In particular, $\tau=1$ if $N$ scales roughly as $L^d$. Our findings reveal that depth plays a more critical role than width in the context of analytic function approximation. The main technical difficulty of obtaining such upper bounds lies in the trade-off between the smoothness parameters and the approximation accuracy. To overcome this difficulty, we employ refined constructions of several ReLU networks to approximate power functions, multivariate multiplication, and
polynomials, which may be of independent interest.
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Machine Learning
MemDecay: Region-Aware KV Cache Eviction for Efficient LLM Agent Inference
Venkatesha Matam and Keon Kim
Large
language model (LLM)
agents accumulate heterogeneous context, including system instructions, plans, user turns, retrieved documents, tool outputs, and intermediate
reasoning, whose key-value (KV) cache can become a major
memory bottleneck. Existing eviction policies generally apply the same
attention- or recency-based rule to every
token, ignoring semantic structure already available to the
agent orchestrator. We introduce MemDecay, a training-free, region-aware KV-cache eviction policy. MemDecay assigns
tokens region-specific base priorities and decay rates, refreshes retention scores when
tokens receive
attention, and evicts the lowest-scoring pages under a fixed cache budget while allowing critical regions to be pinned. We also provide a procedure for calibrating decay rates from measured
attention lifetimes. We evaluate MemDecay at approximately 450 and 1,700
token contexts using Qwen2.5-1.5B and 3B. Across all settings,
attention lifetimes differ by an order of magnitude across regions: system-
token half-lives range from 148 to 189 decoding steps, compared with 14 to 16 for scratchpad
tokens. Pinning preserves system-region facts at full-cache accuracy in every setting, while no baseline preserves more than 13 of 24. Region-aware retention remains effective as context grows, whereas recency-based retention collapses. Accumulated-
attention retention performs better on unpinned content, however, and ablations identify
attention-score normalization as the main limitation of the current formulation. These results establish semantic
prompt structure as a robust signal for KV-cache management while clarifying how it should be combined with
attention-based importance.
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Machine Learning
Learning from Local Walks on Dynamic Graphs with Bandit Feedback
Sourav Chakraborty, Amit Kiran Rege, Claire Monteleoni et al. (+1 more)
We study
stochastic multi-armed bandits on dynamic graphs, where arms correspond to the vertices of a network with time-varying edges. In this setting, the learner is restricted to local movement, selecting only its current node or an immediate neighbor at each round. This constraint decouples best-arm identification from exploitation: even after the optimal arm is identified, the learner may remain unable to reach it through the evolving
topology. We identify a process-agnostic structural condition, based on sliding-window mixing, that ensures the graph's intrinsic walk remains stable for both exploration and
navigation. Under this regime, we analyze a family of local explore-then-commit
algorithms and establish sublinear expected regret. Our framework includes a reward-aware strategy, for which we prove a worst-case safety
theorem and a separate performance gain
theorem.
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All authors Sourav Chakraborty, Amit Kiran Rege, Claire Monteleoni, Lijun Chen
Machine Learning · Cross-listed from cs.SE
When Does Restricting a Coding Agent to execute_code Help? A Regime $\times$ Agent-Design Ablation
Hong Yang, Qi Yu and Travis Desell
Modern coding
agents expose multiple tool surfaces – IDE primitives, bash, and Model Context Protocol (MCP) code-execution – and the field has shipped three contradictory claims about which one matters. We run the missing crossed comparison: an integrity-clean three-arm ablation (baseline / bash_only / code_only) on synthetic computation tasks and SWE-bench Mini modification tasks, holding model, harness, and
prompts fixed, with two
agents (Claude Code, OpenAI Codex CLI) so the comparison spans both regime and
agent-design axes. Across the four resulting (regime,
agent)
cells, restricting the
agent to a single execute_code MCP tool is cheaper than – or statistically tied with – its cheapest tool-rich rival in three
cells (significantly on Artifact/Claude and SWE-bench/Codex; directionally on Artifact/Codex), with pass rates statistically tied within each
cell. The lone exception is SWE-bench/Claude, where code_only is directionally costlier (+14.4%, not significant); a conditional-cost analysis localizes that gap to failure-cost on doomed-run trajectories, not a per-edit tax on successful runs. Two implications: the cheapest tool surface is jointly determined by task regime and
agent design rather than by either axis alone, and the headline cost signal lives in cache-adjusted cost – not pass rate, which is invariant across surfaces at the model sizes we evaluate. The
benchmark harness, task suite, and analysis code are available at https://github.com/hyang0129/onlycodes.
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Machine Learning · Cross-listed from cs.RO
BucketKD: A Safety-Aware Bucket-Based Knowledge Distillation Framework for End-to-End Motion Planning
Md Nahidul Islam, Mohd Hasan Ali, Dipankar Dasgupta et al. (+1 more)
End-to-end motion planning has emerged as a promising paradigm in autonomous driving, directly mapping raw sensor data to control commands via deep neural networks. Despite its advantages, its large model size hinders deployment in resource-constrained platforms. In this paper, we present BucketKD, a bucket-based knowledge
distillation framework that yields compact and safety-aware end-to-end planners. Compared to the state-of-the-art approach, which relies on simplified planning state representations, BucketKD discretizes critical environmental variables into adaptive buckets that capture richer scene semantics while preserving efficiency. In addition, we design a safety-aware waypoint
attention mechanism that evaluates each waypoint's risk level by accounting for both obstacle proximity and relative motion through a time-to-collision (TTC) formulation widely used in transportation research. This enables the student model to better retain safety-critical behaviors during
distillation. Extensive experiments in CARLA using the Bench2Drive
dataset show that BucketKD significantly outperforms the state-of-the-art in both planning accuracy and safety while maintaining strong compression ratios.
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All authors Md Nahidul Islam, Mohd Hasan Ali, Dipankar Dasgupta, Myounggyu Won
Machine Learning · Cross-listed from stat.ME
Observation-Level Watermarking and Detection for Tabular Data
Dongyu Cui and Xuan Bi
With the development of generative AI, watermarking techniques have been widely used to detect the authenticity of AI-generated data and protect the rights of users and creators. While it is already well applied in data types including imaging and text data, watermarking tabular data is still under-explored. Existing methods primarily focus on numerical data, leaving discrete, categorical, and mixed data less studied. In this work, we propose STAMP (Single-observation Tabular Attribution and Marking Procedure), a novel framework for watermarking tabular data that can accommodate and preserve a wide range of distributions. We also develop a corresponding detection mechanism, which can reliably identify watermarks even when the sample size is as small as one. We establish theoretical guarantees for asymptotic consistency and detection accuracy. Finally, through extensive simulation studies and two real-data applications, we demonstrate that the proposed method is effective and robust to subsetting, while maintaining data fidelity and a high detection rate.
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Machine Learning · Cross-listed from eess.IV
Projection-Domain Sensitivity Analysis of Vertebral DRRs Under Intrinsic Calibration Perturbation
Lin Li, Chaochao Zhou, Benjamin Aubert et al. (+2 more)
Accurate
geometric calibration is essential for fluoroscopy-guided spinal imaging, digitally reconstructed radiograph (DRR) generation, and 2D–3D vertebral registration. Although calibration quality is typically evaluated using reconstruction-based metrics such as reprojection error, its influence on projection-domain consistency remains poorly understood. This study presents a synthetic framework for evaluating how intrinsic calibration perturbations affect vertebral fluoroscopic projections and downstream registration performance. CT-derived vertebral models and controlled cone-beam imaging geometry were used to generate DRRs with both ground-truth and perturbed intrinsic calibration parameters while maintaining identical anatomy and acquisition pose. Projection-domain changes were quantified using anatomical landmark displacement, contour distance, silhouette overlap, image similarity, and landmark-based 2D–3D registration accuracy in anterior–posterior (AP) and lateral (LAT) views. Results show that even small intrinsic calibration perturbations produce measurable changes in vertebral projection geometry, contour morphology, landmark localization, and DRR appearance. Sensitivity is strongly view dependent, with LAT projections exhibiting substantially greater deformation and anatomical displacement than AP projections. These projection inconsistencies also degrade downstream 2D–3D registration, particularly rotational
alignment accuracy. The findings demonstrate that projection-domain consistency complements conventional reconstruction-based calibration metrics and provides a practical framework for assessing calibration robustness. This approach may improve the reliability of DRR generation and fluoroscopy-guided vertebral registration in image-guided spinal applications.
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All authors Lin Li, Chaochao Zhou, Benjamin Aubert, Junlin Guo, Junchao Zhu
Machine Learning · Cross-listed from stat.ML
Beyond Looking Up, Try Looking Around: Harmonizing Global Structure and Local Consistency in Optimal Transport for Short Text Clustering
Zhihao Yao, Yuxuan Gu, Jixuan Yin et al. (+1 more)
Pseudo-labeling based on Optimal Transport (OT) has become an effective mechanism for enhancing short text clustering. Existing OT methods are short in modeling semantic consistencies between samples, which may assign different pseudo-labels to semantically similar samples. These erroneous pseudo-labels can cause the model to produce inferior clusters. This paper proposes a novel short text clustering framework, which remedies the neglect of semantic consistency in existing OT methods, generating reliable pseudo-labels to facilitate clustering. Specifically, the proposed approach first designs an instance-level
attention mechanism to capture semantic relationships between samples, which are then integrated into the OT formulation to endow the transport process with neighborhood semantic awareness. By solving the proposed OT formulation, reliable pseudo-labels are obtained that simultaneously account for sample-to-sample semantic consistency and sample-to-cluster global structure information. These pseudo-labels are then used as supervisory signals to guide the model to achieve accurate clustering. Extensive experiments demonstrate that the proposed approach outperforms state-of-the-art methods. The code is available at: \href{https://github.com/YZH0905/CAOT-STC}{https://github.com/YZH0905/CAOT-STC}.
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All authors Zhihao Yao, Yuxuan Gu, Jixuan Yin, Bo Li
Machine Learning
LLM-PDESR: Robust PDE Discovery via Subdomain Weighted Residuals and LLM-Guided Symbolic Hypothesis Generation
Jinyang Du, Hao Ma, Xiaohu Shi et al. (+4 more)
Discovering governing partial differential equations (PDEs) from noisy observational data is a fundamental challenge in scientific machine learning. Traditional symbolic regression (SR) methods often struggle to identify accurate equations within vast combinatorial search spaces, largely due to their inability to incorporate essential domain-specific prior knowledge. Furthermore, reliance on pointwise evaluations and discrete finite differences inherently amplifies high-frequency noise, creating deceptive fitness landscapes that derail the optimization process. To resolve these bottlenecks, we propose LLM-PDESR, a framework that integrates the structural hypothesis generation of Large
Language Models (LLMs) with a mathematically rigorous evaluation environment. By employing C^4-continuous quintic splines for robust differentiation and subdomain weighted residuals as natural low-pass filters, our approach effectively mitigates the fitness landscape distortion that plagues existing methods. A Pareto-driven feedback loop then enables the LLM to iteratively refine candidate equations, balancing predictive accuracy with structural parsimony. We evaluate LLM-PDESR on 23 canonical PDEs and five structurally novel equations (including a multivariate system) specifically designed to preclude
dataset memorization and test true discovery capabilities. Demonstrating real-world applicability, the framework successfully extracts a consistent structural skeleton for an interpretable 1D dynamical surrogate (1D-CACE) directly from noisy ERA5 reanalysis data. Extensive experiments and out-of-distribution testing confirm that LLM-PDESR significantly outperforms state-of-the-art methodologies in structural recovery, noise resilience, and the avoidance of spurious complexity and equation bloat.
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All authors Jinyang Du, Hao Ma, Xiaohu Shi, Bo Yang, Yanchun Liang, Heow Pueh Lee, Chunguo Wu
Machine Learning · Cross-listed from cs.IR
RecRec: Recursive Refinement for Sequential Recommendation
Pervez Shaik, Prosenjit Biswas, Abhinav Thorat et al. (+2 more)
Sequential recommender systems typically infer user preferences through single-pass encoding of interaction histories without iterative refinement, relying on increasingly deep architectures to capture complex patterns. In this work, we revisit sequential recommendation from a recursive inference perspective: can user preferences be modeled as a persistent latent state that is recursively refined? We propose RecRec (Recursive Recommendation), a lightweight model that maintains a compact latent state and updates it through a shared recursive module conditioned on interaction evidence. Unlike prior recursive models, RecRec introduces an evidence-anchored correction mechanism that stabilizes refinement by grounding each update in the original interaction context, preventing semantic drift during deep recursive
reasoning. Experiments on three
benchmark datasets under standard evaluation protocols show that RecRec matches or outperforms state-of-the-art sequential, graph-based, and
reasoning-enhanced recommenders while using only 3.9M to 14M parameters. Ablation studies demonstrate that both recursive refinement and the evidence-anchored correction gate contribute significantly to performance, highlighting the effectiveness of recursive latent inference as a scalable alternative to deeper or
language-based architectures. Code is available at https://anonymous.4open.science/r/RecRec-6B67/README.md.
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All authors Pervez Shaik, Prosenjit Biswas, Abhinav Thorat, Ravi Kolla, Niranjan Pedanekar
Machine Learning · Cross-listed from stat.ML
Representation Learning for Semiparametric Causal Mediation Analysis under No Essential Heterogeneity
Roberto Faleh, Sofia Morelli and Holger Brandt
We propose a two-stage
estimator for structural mediation parameters that combines deep representation learning with G-estimation under the "no essential heterogeneity" (NEH) assumption. We call the method UNIT. In the first stage,TARNet estimates the heterogeneous effect of a randomized treatment on a mediator by learning a shared
covariate representation across treatment arms.The resulting conditional average treatment effect (CATE) estimate provides a plug-in approximation to the heterogeneity-dependent component of the weight function entering the G-estimating equation of Zheng and Zhou (2015), which identifies the structural parameters even in the presence of unmeasured mediator-outcome confounding. We show that more accurate first-stage representation learning can yield a more informative plug-in weight and thereby improve the precision of the structural parameter
estimator. In simulations with non-Gaussian
covariates and nonlinear mediator effects, TARNet weights reduce the Stage-2 standard error of the mediation coefficient by a factor of $1.45$ to $1.51$ (median across replications, $n \ge 2000$) relative to the classical approach, at no cost to bias or coverage.
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Machine Learning · Cross-listed from cs.AI
Cross-Layer Misalignment Detection in Agent Skills: A Progressive Loading-Aware Contrastive Learning Approach
Chengjun Zhang, Yang Gao, Jianna Hur et al. (+2 more)
Large
language model (LLM)
agents are increasingly extended through
Agent Skills, reusable artifacts that package natural-
language metadata, procedural instructions, and execution-time resources for runtime use. As open-source skill marketplaces expand, users and
agents increasingly rely on brief metadata to select third-party skills, making it difficult to detect inconsistencies between a skill's description and its true behavior, a problem we call cross-layer misalignment. To address this issue, we propose Progressive Loading-Aware Hierarchical Contrastive Learning (PL-HCL), an LLM-based framework that detects misalignment by modeling the layered structure of
Agent Skills and learning cross-layer consistency. Using a normalized corpus of over 264,000 open-source skills and a human-verified challenge set, PL-HCL improves Macro-F1 from approximately 0.45 for unadapted baselines to 0.87-0.89 across evaluated LLM backbones. This approach offers an effective screening tool for users and operators, as well as design principles for detecting inconsistencies in layered digital artifacts.
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All authors Chengjun Zhang, Yang Gao, Jianna Hur, Jingjing Zhang, Sagar Samtani