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cs.CV Adam Lee, Mutian Xu, Yukang Cao et al. · Oct 22, 2026

DeXplicit addresses action-conditioned world modeling for dexterous manipulation by splitting prediction into an explicit metric 3D dynamics stage and a subsequent video rendering stage. Instead of entangling physics, viewpoint, and appearance in a monolithic video generator, it first forecasts structured object motion and deformation, then uses those predictions as geometric scaffolds for efficient causal video synthesis. The core claim is that making physical state explicit improves both geometric accuracy and generation speed.

Before acting on an object, a robot needs to anticipate how its hand motion will change the physical world and what the resulting scene will look like. Existing approaches typically entangle action-conditioned dynamics, camera motion, and visual synthesis within a video generation model, or represent dynamics as point trajectories without explicit object structure. We introduce DeXplicit, a dexterous manipulation world model that instead predicts how the world evolves explicitly in metric 3D before rendering its visual consequences. Given an initial scene and a future hand trajectory, a lightweight 3D dynamics network predicts object-centric motion and deformation, providing structured and geometrically grounded future world states. These predictions then serve as a strong scaffold for video generation: appearance is transported through the predicted 3D motion and projected into future views, allowing the renderer to focus on completing uncertain and newly visible content rather than implicitly learning world dynamics from pixels. This explicit-3D-first decomposition also enables efficient causal generation, requiring only two denoising steps per block while conditioning on generated history. Across HOT3D, OakInk2, and PhysTwin, DeXplicit reduces moved-point error by 27-40% relative to PointWorld and improves object fidelity IoU+ by 47% on HOT3D under a shared renderer. Our design with two-step causal generation achieves a 57x speedup from our 14B bi-directional configuration in video synthesis.
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cs.CV Wei Zhang, Ying Feng, Mengtong Wu et al. · Oct 22, 2026

Stream4D tackles online 4D reconstruction in dynamic scenes, where moving objects break static-scene assumptions and cause pose drift and ghosting artifacts in causal streaming pipelines. The core idea is a training-free plug-in that mines temporal motion cues from the KV cache of causal Transformers, fuses them with depth priors to generate dynamic masks, and suppresses dynamic keys via soft masking to prevent interference during historical aggregation. By operating directly on cached keys without architectural changes or retraining, it aims to make existing streaming backbones like Stream3R and StreamVGGT robust to dynamic content while retaining linear-time scalability.

4D scene reconstruction requires robust handling of dynamic objects, yet existing streaming methods commonly assume static scenes, leading to pose drift and ghosting artifacts over long sequences. We introduce Stream4D, a training-free, motion-decoupled streaming reconstruction framework that can be directly integrated into causal Transformer backbones (e.g., StreamVGGT, Stream3R). Our key observation is that causal attention implicitly encodes rich temporal motion cues within the KV cache. We adaptively aggregate these cues from multiple attention layers and across temporal windows, and fuse them with depth priors to handle challenging cases such as occlusions and textureless regions, producing precise dynamic masks that decouple static and dynamic regions. We then apply a soft key masking scheme that leverages these dynamic masks to suppress interference from dynamic regions in causal attention, thereby improving camera pose estimation accuracy. Stream4D inherits the efficiency of causal attention and remains compatible with existing streaming architectures. On diverse dynamic-scene benchmarks, Stream4D significantly improves camera pose estimation and static-scene reconstruction quality, yields reliable dynamic masks, and effectively mitigates long-sequence ghosting.
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cs.CV Guillem Casadesus Vila, Grace Gao · Oct 22, 2026

Future lunar rovers will navigate tens of kilometers using cameras, but the feature detectors and matchers at the heart of visual odometry are benchmarked almost exclusively on urban and driving scenes. This paper evaluates eleven classical and learned detector–matcher combinations on nine synthetic, lunar-testbed, and terrestrial-analogue datasets, measuring how pairwise pose accuracy degrades with viewpoint change and how the resulting correspondences drive open-loop VO error. The central finding is that learned SuperPoint pairings outperform classical SIFT on real low-texture lunar terrain and remain robust across lighting, yet synthetic datasets alone are misleading predictors of real performance and the learned advantage narrows when short-baseline translation direction is scored jointly. The work directly addresses a critical gap for Artemis-era rover autonomy by showing precisely where classical front ends fail and under what conditions learned ones are worth their computational cost.

Lunar rovers will primarily rely on cameras for localization until navigation satellite services are deployed, and will continue to need them afterwards for relative navigation, hazard detection, and surface operations. Visual odometry (VO) and Simultaneous Localization and Mapping (SLAM) mostly estimate motion by matching features between frames. However, feature matchers are developed on urban, indoor and driving scenes, planetary studies compare them on orbital registration or within complete SLAM systems, and real lunar imagery with reference poses is scarce, so matching between rover frames on low-texture, harshly lit terrain, and its effect on VO, has not been compared. We benchmark eleven classical and learned detector-matcher combinations on nine synthetic, lunar-testbed, and terrestrial-analogue datasets, and a feature tracker, scoring pairwise pose accuracy against baseline and the trajectory error of the resulting VO. Under a common rotation-only metric, the SuperPoint pairings outperform SIFT with ratio-tested FLANN matching on both lunar testbeds and one analogue site, with smaller or unresolved differences on synthetic data. When rotation and translation direction are scored jointly, this SIFT pairing exceeds both SuperPoint pairings on four synthetic datasets, so synthetic results alone do not establish relative performance on real rover imagery. In stereo VO, the SuperPoint pairings are not consistently more accurate than SIFT, but only they keep tracking on all eight sequential datasets. Pairings with classical detectors depend on lighting while SuperPoint changes little: a low spotlight makes them more accurate than diffuse light on the same testbed views, consistent with more contrast and detected keypoints. SuperPoint with LightGlue is the fastest learned combination (16 ms per frame), and DINOv2 retrieval proposals still need geometric verification.
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math.SGmath.APmath.DG Viktor Stein, Levin Maier, Wuchen Li et al. · Oct 22, 2026

Transformer attention is commonly viewed as an interacting particle system, yet the mean-field limit on probability densities over $\mathbb{R}^d$ lacks rigorous geometric foundations on non-compact domains. This paper derives accelerated attention blocks from Nesterov-type damped Hamiltonian dynamics on spaces of probability measures, introducing a local-mobility geometry for softmax attention and a quotient Stein geometry for linear attention. The theory yields sharp PDE well-posedness and finite-time blow-up results, plus quantitative links to token-norm growth across discrete layers. Small-scale language-modeling experiments report minor validation-loss improvements at increased computational cost.

The attention mechanism underpins modern large language models, yet their dynamics remain only partially understood. Recent perspectives interpret attention blocks as interacting particle systems, whose mean-field limits correspond to gradient flows of energy functionals on spaces of probability densities on $\mathbb R^d$ equipped with Wasserstein-type metrics. We extend this viewpoint by deriving accelerated attention blocks from inertial, Nesterov-type damped Hamiltonian dynamics on these density spaces, developing the geometry and differential calculus needed to make the construction rigorous. In particular, we introduce a local-mobility geometry for the Otto-Wasserstein and softmax-Wasserstein settings, and a quotient Stein geometry that resolves the degeneracy of the linear-attention kernel to yield a well-defined metric and differential calculus. We provide rigorous foundations when softmax attention admits a gradient-flow formulation and when its inertial counterpart admits a damped Hamiltonian on explicitly characterized domains. For linear attention, we obtain a finite-dimensional solution theory with sharp conditions for global existence versus finite-time second-moment blow-up. We further prove a quantitative link between continuous moment blow-up and the discrete-layer depth at which token norms cross a prescribed threshold. Finally, motivated by the finite-token geometry, we propose geometric corrections to token and momentum updates. In decoder-only, nanoGPT-style experiments on TinyStories and OpenWebText, these corrections lower validation negative log-likelihood on next-token prediction relative to momentum-only controls.
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cs.CV Ariel Lapid, Yuval Haitman, Reuven Peretz et al. · Oct 22, 2026

GLOW-FM attacks the high inference cost of diffusion-based low-light image enhancement (LLIE) by replacing iterative sampling with a single-step latent flow. The core idea is to run Terminal Velocity Matching (TVM) in the compact latent space of a frozen Tiny-VAE, directly predicting the displacement from a degraded low-light latent to its well-exposed counterpart in one function evaluation. If its quality claims hold up, the result would be a generative LLIE method practical enough for edge-device deployment.

Low-light image enhancement (LLIE) aims to recover well-exposed and perceptually faithful images from severely degraded observations. Recent diffusion-based generative methods achieve strong perceptual quality by leveraging powerful image priors, but their iterative sampling incurs substantial computational cost, limiting practical deployment. Despite recent efficiency gains in generative LLIE, high-quality enhancement with a single function evaluation and low overall computation remains challenging, particularly under diverse real-world low-light conditions. We introduce GLOW-FM, a one-step latent flow-matching framework for efficient generative LLIE. GLOW-FM performs conditional transport in the latent space of a frozen Tiny-VAE and leverages Terminal Velocity Matching (TVM) to enable enhancement with a single function evaluation. Matched comparisons with alternative one-step objectives support TVM as an effective design choice, and, to the best of our knowledge, this is its first adaptation to image restoration and specifically to LLIE. Extensive experiments on challenging real-world benchmarks demonstrate that GLOW-FM achieves competitive image quality and state-of-the-art cross-dataset generalization while requiring only a single function evaluation and 34 GFLOPs for the small variant. These findings highlight the potential of GLOW-FM to bring generative LLIE closer to practical deployment through single-step inference and compact latent modeling. Code will be made publicly available upon publication.
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stat.MLcs.LG R\'emy Chapelle (CB, EVDG, CESP) · Oct 22, 2026

High-dimensional nonparametric density estimation is notoriously plagued by the curse of dimensionality. This paper proposes to factorize the joint distribution autoregressively into a product of one marginal and $d-1$ conditional densities, estimating each factor with parallel gradient boosting (PGB), a fast tree-based multi-quantile regression method. The authors prove that for subadditive divergences the joint convergence rate is governed by the hardest factor, and that when conditional estimators adapt to sparsity the optimal rate relates to the treewidth of an underlying dependence graph. Together, the theory and experiments suggest that flexible autoregressive factorization offers a practical off-the-shelf alternative to kernels, copulas, and random forests for moderate-to-high dimensional continuous data.

Nonparametric estimation of joint probability distributions is a core problem in statistics, which is notoriously challenging with high-dimensional data. Such challenges also arise with conditional distribution estimation and have led to flexible algorithms that aim to tackle the ''curse of dimensionality'' by exploiting predictive structures of lower dimension than the ambient space. In this paper, we study the use of such conditional distribution estimators to estimate joint distributions by factorizing the latter in an ''autoregressive'' way. We show that for loss functions satisfying a subadditivity property, bounds on the convergence rate of an autoregressive estimator can be derived from bounds on the convergence rate of the conditional distribution estimators. These bounds relate the difficulty of estimating the joint distribution to that of estimating the most challenging factor in the autoregressive factorization. When the conditional estimators adapt to sparsity in their conditioning sets, we characterize this difficulty through variable elimination in an undirected dependence graph. This allows bounding the rates of convergence by quantities related to the sparsity of the graph, and provides an additional motivation for the autoregressive approach. We then evaluate the practical performance of an autoregressive estimator based on parallel gradient boosting, a flexible nonparametric method for estimating conditional distributions. The estimator demonstrates competitive estimation performance on various simulated and real datasets, even without optimizing the factorization order. Together, these results support nonparametric autoregressive estimation as a practical approach to flexible joint distribution estimation.
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cs.CV Qiwen Gu, Xin Zhou, Xiwu Chen et al. · Oct 22, 2026

FlexPart addresses a key limitation in controllable 3D asset creation: existing image-to-3D part generation systems are typically specialized for a single prompt type, forcing users into rigid workflows. The paper introduces a unified Diffusion Transformer framework that simultaneously accepts sparse point prompts, 2D bounding boxes, and dense masks via Gated Adaptive Layer Normalization, while an Asymmetric Geometric Guidance mechanism uses differentiable optimal transport to let dense spatial priors supervise sparse representations during training. By jointly training across prompt granularities, the method aims to improve part-level geometric fidelity and give users flexible control over how they specify structure.

Controllable 3D part generation is pivotal for digital asset creation, yet existing methods lack the flexibility to accommodate diverse user workflows requiring varying levels of control. In this paper, we introduce FlexPart, a unified image-to-3D part generation framework that supports variable-granularity geometric conditions within a single model. By seamlessly integrating heterogeneous inputs, ranging from sparse points to dense bounding boxes and masks, via gated adaptive modulation, FlexPart unlocks a powerful cross-modal synergy. We also propose an asymmetric geometric guidance mechanism that leverages strong spatial priors to align representations across granularities, improving geometric consistency and facilitating inter-task synergy. Under mask conditioning on PartVerseXL, FlexPart reduces Part CD by 16.6% relative to TripoSG + SAM3D and by 10.5% relative to OmniPart, while maintaining competitive whole-mesh quality. The code can be found at https://github.com/Gucci233/FlexPart
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cs.CV Wenhua Jin, Tiancheng Chen, Sheng Tang et al. · Oct 22, 2026

Motion segmentation is conventionally treated as an object-level property, causing entire instances to be marked moving even when only a small part displaces or when the camera itself moves. This paper reframes motion as a relation between an ordered source–target frame pair and proposes MoRSe, a feed-forward model that predicts moving-region masks without optical flow, point tracks, or a frozen segmentation foundation model at inference. To support this formulation the authors introduce MoRSe-5K, a benchmark with Static, Dynamic-Static, and Dynamic splits that directly measures whether a model can suppress false positives under pure camera motion.

Moving object segmentation is conventionally formulated at the sequence and object level, marking an entire instance as moving once it moves anywhere in a video. Recent instantaneous formulations distinguish moving from stationary intervals, but still generate masks at the object level through frozen segmentation foundation models. Because the mask is derived from an instance-level proposal, motion is typically attributed to the entire instance rather than localized to the regions that actually move. Moreover, such instance-level predictions can produce masks even when no part of the instance is actually moving, revealing a more fundamental issue: motion is not an intrinsic property of an instance; it can only be determined by comparing at least two frames. Building on this premise, we introduce MoRSe, which jointly interprets two frames to predict a moving-region mask, distinguishing actual scene motion from apparent motion induced by the camera. A single RGB encoder replaces multi-stage foundation stacks, so no optical flow, point tracks, or separate mask generator is needed at inference. We release MoRSe-5K, a benchmark of 42 sequences with Static, Dynamic-Static, and Dynamic settings designed to evaluate the model's ability to distinguish and localize moving and stationary regions under different camera and scene motion conditions. MoRSe outperforms both specialized moving object segmentation methods and dense 4D reconstruction methods with motion-thresholded predictions, while producing the fewest false positives on sequences where nothing moves.
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cs.LG Sarah Liaw, Yuanqi Du, Yilun Du · Oct 22, 2026

Scientific inference often requires evaluating and optimizing complete trajectories, yet existing methods typically learn local one-step dynamics or train black-box generators that lack a reusable path objective. This paper proposes action learning, the task of recovering a stochastic action from trajectory observations, and introduces LEAP, which learns a path-space correction relative to a tractable reference process via noise-contrastive trajectory comparisons. By constructing a differentiable objective on complete paths, LEAP captures nonadditive temporal dependencies and enables downstream reuse for ranking, constrained inference, and sampling without retraining.

Understanding and controlling how systems evolve is central to science and engineering, where many problems require reasoning about complete trajectories. Existing approaches typically learn local dynamics or generate trajectories, but objectives constructed from individual transitions can miss dependencies across time, while generative models do not necessarily provide a tractable objective for evaluating and optimizing arbitrary paths. We study $\textit{action learning}$, the problem of recovering a stochastic action from trajectory observations, yielding a common objective for reasoning about dynamical systems. We introduce $\textbf{LEAP}$ ($\textbf{L}$earned $\textbf{E}$nergy on $\textbf{A}$ction $\textbf{P}$aths), which anchors the unknown action to a tractable reference process and learns the remaining correction by comparing observed trajectories with reference trajectories. This construction yields a differentiable objective on path space that can capture both local dynamical structure and nonadditive dependencies across time. Once learned, the same action can be flexibly reused for path ranking and inference, mechanism steering, constrained optimization and sampling. Across stochastic physical systems, many-body orbital dynamics and molecular simulations, LEAP recovers underlying dynamics, captures dependencies across time and enables transfer across inference objectives and physical conditions. We show that $\textit{action learning}$ is a promising framework for turning trajectory observations into reusable objectives for scientific inference and control.
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cs.CV Nimrod Shabtay, Asaf Yehudai, Avihu Dekel et al. · Oct 22, 2026

Vision-language models lag at visual in-context learning because they exploit textual shortcuts rather than learning from demonstration images. This work argues the root cause is insufficient training data that forces pure visual induction, and proposes MIME—a synthetic, task-agnostic dataset where the rule is never stated in text—and DTAD, a label-dropout mechanism that shifts attention to visual tokens. The result is an 8.1–18.0 point jump in vICL accuracy across multiple architectures, with an 8B model matching frontier proprietary systems, suggesting vICL-specific data should become a standard ingredient in VLM training.

Vision-language models (VLMs) struggle with in context learning compared to their textual counterparts. Our preliminary study shows that VLMs rely on textual shortcuts and underutilize the visual demonstrations. We therefore hypothesize that VLMs are insufficiently trained to perform visual in-context learning (vICL). To this end, we construct MIME, a task-agnostic vICL training set without textual shortcuts. We ensure the instruction does not state the rule linking the demonstration images to their answers, so the model must infer it from the visual demonstrations. Fine-tuning on MIME improves vICL accuracy by 8.1 to 18.0 points across three VLMs, preserves single-image performance, and improves multi-image and text only in-context learning. In contrast, stating the rule in the training data sharply reduces this gain. We further propose DTAD (Demonstration Text Attention Dropout), which randomly withholds demonstration labels during training so that the VLM must infer the rule from the demonstration images. While achieving comparable vICL accuracy to fine-tuning on MIME, DTAD yields more consistent attention to the demonstration images. On TrueMICL, Qwen3-VL-8B trained on MIME matches frontier models such as Claude Opus 5, and surpasses them with DTAD. Finally, adding MIME to the instruction-tuning mix of LLaVA 1.5 13B more than doubles its vICL accuracy without hurting single-image abilities, whereas a same-size multi-image set improves it only slightly. These results suggest that vICL data should be a standard component of VLM training.
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eess.IVcs.CVcs.GR Zhang Zichuan, Bart Brouwers, Rembrandt Bakker et al. · Oct 22, 2026

H-2DGS addresses the need for sharp, photorealistic neurosurgical surface reconstruction that can fuse with MRI and tractography without obscuring internal brain structures. The authors propose a three-stage pipeline that bootstraps appearance with conventional 3D Gaussian Splatting, contracts volumetric density along camera rays using differentiable quantiles, and converts the fused TSDF surface into curved height-field Gaussian patches. By explicitly representing a thin, deformable cortical sheet rather than a diffuse volume, the method targets geometric precision and compactness at the cost of some rendering fidelity.

Neurosurgical navigation commonly presents magnetic resonance imaging (MRI) as 2D slices, making it difficult to relate the anatomy in those slices to the cortical surface observed through the surgical microscope. We seek a common 3D visualization that combines a photorealistic reconstruction of the exposed cortex during tumor surgery with whole-brain MRI context and diffusion tractography pathways. This requires the reconstructed cortex to form a clear boundary around the brain anatomy rather than a diffuse volume that obscures internal structures. Conventional 3D Gaussian Splatting (3DGS) can reproduce observed views but, under limited surgical view coverage, may distribute opacity through a thick and geometrically ambiguous band. We introduce height-field 2D Gaussian Splatting (H-2DGS), a three-stage pipeline that concentrates a robust 3DGS reconstruction, fuses its depth into a shared truncated signed distance field (TSDF) surface, and represents that surface with curved, surface-oriented Gaussian primitives. Separate height, color, and opacity bases provide local geometry and appearance, while a neighbor-transition objective coordinates overlapping patches. The explicit surface further supports postoperative alignment: MRI-derived depth deforms the reconstruction, and tracked-color supervision with alternating optimization preserves its appearance. Across five real neurosurgical cases, H-2DGS gives low multi-view depth inconsistency, a compact 7.97MB representation, and interactive rendering at 29--42ms per frame. The resulting sharp, deformable surface integrates clearly with tractography and MRI anatomy, including a postoperative resection cavity.
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cs.CV Ronald Fecso, Jos\'e Morano, Botond Fazekas et al. · Oct 22, 2026

Multimodal large language models can answer clinical questions about retinal OCT scans, but without spatial grounding clinicians cannot verify whether a model attended to real pathology or relied on spurious shortcuts. This paper introduces RetinaGroundBench, the first benchmark for biomarker visual grounding in retinal OCT, together with $AggIoU$—a metric tailored to MLLMs that fragment lesions into multiple boxes—and RetGrounder, an 8B domain-adapted model that outperforms general-purpose models up to 38B parameters. The core message is that grounding remains largely unsolved: even the best open-source model achieves only 23.7% macro $F_1$, and VQA ability does not imply localization skill. The work matters because trustworthy clinical deployment of MLLMs requires precisely this kind of verifiable spatial evidence.

Multimodal large language models (MLLMs) can answer clinical questions about medical images, but trustworthy use requires visual grounding: models should localize the pathology they report rather than rely on spurious shortcuts. Whether MLLMs can visually ground clinical findings in retinal optical coherence tomography (OCT), the most widely used imaging modality in ophthalmology, remains largely unexplored. To address this gap, we introduce RetinaGroundBench, the first benchmark for biomarker visual grounding in retinal OCT. It comprises 815 B-scans exhaustively annotated by ophthalmologists with 4,537 bounding boxes covering 13 biomarkers across 8 diseases. Because MLLMs often fragment a single lesion into multiple partial predictions, we propose AggIoU, a metric that evaluates whether the union of overlapping predicted boxes covers the annotated region. Across 27 open-source MLLMs (0.8-38B parameters), we find that visual grounding remains largely unsolved: the best general-purpose model achieves a macro F1 of just 23.7%, with consistently low recall, despite reaching up to 73% balanced accuracy on biomarker presence questions. To narrow this gap, we developed RetGrounder, an MLLM fine-tuned using an OCT-specific strategy integrating grounding and textual information. Despite its relatively small size (8B), RetGrounder improves grounding F1 to 33.9%, a 43% relative improvement. Our benchmark provides a reference point for measuring progress in the field of OCT diagnosis with MLLMs.
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cs.CV Y. Li, M.Bigliardi-Qi, S. Bedros et al. · Oct 22, 2026

This paper audits SkinCon, a widely used dermatology concept dataset, for skin-tone-dependent annotation bias.
Within the same disease, erythema is labeled far less often on dark skin (odds ratio 0.17) while pigmentary concepts are labeled more often.
An evidential concept model trained on these annotations reproduces the bias, and three label-error detectors fall below a disease-only baseline at catching potential erythema omissions.
The work warns that concept bottleneck explanations for skin disease diagnosis cannot be trusted until annotations are audited within each subgroup.

Concept bottleneck models (CBMs) let clinicians inspect and correct skin disease diagnoses through clinical concepts, but only if the concept annotations are reliable. We therefore audit the reliability of SkinCon, a widely used dermatology concept dataset, across skin tones. Within the same disease and with near duplicates removed, erythema is annotated far less often on dark than on light skin, with an odds ratio of 0.17. In contrast, hyperpigmentation and hypopigmentation are annotated more often, with odds ratios of 6.2 and 4.5, respectively. We refer to this pattern as tone-dependent concept annotation. An evidential concept model trained on these annotations learns the same pattern and reproduces it on unseen images. Such a model may agree with potential erythema omissions rather than contradict them. Consistent with this, three label error detectors underperform a disease-only baseline at finding erythema that dermatologist captions mention but SkinCon labels as absent. The three detectors are based on confident learning, training dynamics, and the model's own evidential uncertainty. Concept annotations should thus be audited within each subgroup before explanations built on them can be trusted.
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cs.CV Yuanze Hu, Zhichao Yang, Junwei Jing et al. · Oct 22, 2026

Detailed image captioning is usually treated as a global coverage task, but captions are generated as ordered sequences where later tokens can degrade in different ways. This paper introduces a position-aware rubric that decomposes captions into quartile-wise supported, hallucinated, and generic content, exposing two distinct failure modes: mid-caption unsupported specificity and tail generic escape. Motivated by this diagnosis, the authors propose PAGER, a GRPO reward with separate signals for middle evidence, tail density, and length control, achieving strong pairwise wins while preserving competitive global quality metrics.

Detailed image captioning is usually framed as an amount problem: a model should mention more visual facts while avoiding hallucination. However, autoregressive VLMs generate captions as ordered sequences, and later generations may be produced under weaker or noisier visual grounding. We therefore argue that long-form captioning should be studied not only by what facts are mentioned, but also by where they appear. We introduce a position-aware rubric representation that decomposes dense human references into atomic visual claims, verifies generated captions against those claims, and induces a quartile-wise composition of supported, hallucinated, and generic content. This lens reveals two qualitatively different failures in long captions: models tend to produce unsupported specificity in the middle, while the final portion often escapes into vague, non-evidential language rather than simply accumulating more hallucination. A same-reference human control does not exhibit these patterns; additional human audits examine the visual validity of the induced labels. Motivated by this diagnosis, we propose PAGER (Position-Aware Grounded Evidence Reinforcement), a GRPO training objective with separate signals for supported fine-grained middle evidence, evidence-bearing tail continuation, claim coverage, and content-aware length control. The result is a closed loop: the same ordered claim representation identifies where long captions fail and supplies the position-specific reward needed to repair those failures. Experiments on detailed-caption benchmarks show that PAGER improves position-wise grounding and pairwise caption preference while preserving competitive global caption quality.
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cs.CEcs.LGcs.NA Miguel A. Aguilo · Oct 22, 2026

The paper presents structure-preserving reduced-order models for two high-speed aeroelastic challenge problems—a clamped panel at Mach 1.92 (RC-19) and a cantilever plate at Mach 5.85 (HyMAX). Because the experimental packages lack time-resolved responses or repeated runs, the author proposes a learned model that retains the exact physics-based potential energy, fits generalized aerodynamic and damping forces by least squares, and trains only a dissipation matrix engineered to remain positive definite. An exact discrete-gradient integrator then guarantees an energy balance to machine precision regardless of the trained parameters, aiming to show that physical structure, not large datasets, can carry predictive capability in chaotic flutter regimes.

We build structure-preserving reduced-order models for both challenge problems of the AePW-4 High-Speed Working Group. They are a clamped thin panel at Mach 1.92 (RC-19) and a cantilever plate at Mach 5.85 (HyMAX). The published data for each case hold no time-resolved response and no repeated runs. The physics must therefore be carried by the form of the model. One construction gives two models per problem. A Ritz-Galerkin reference model describes the plate. A learned model keeps the reference model's exact potential, fits the remaining generalized forces, and trains only a dissipation that cannot add energy. Its energy balance holds for any weights by construction. On the trained model the worst relative residual is 2.2e-15. On RC-19, shock relations predict a pressure ratio of 1.521 across the panel. Pressure-sensitive paint measured the same value. Thirty runs of the learned model place the mean dominant frequency within 1.0% of the measured 236 Hz. At one periodic and one chaotic condition, the learned model reproduces the response regime of a published reduced-order model in all sixteen runs. It does so without that model's 113 Hz spectral peak, which the measurements do not show. Measured displacements can also correct the chaotic response through one more force that respects the energy balance. We tested this on synthetic data at the experiment's 5 kHz sampling rate. The state error is 1.25% of the panel thickness without noise and 3.5% with 10 micrometers of noise. On HyMAX the learned model follows the reference model's trailing-edge displacement for 65 ms with a relative error of 3.7%. These results show that a model whose structure carries the physics can match measured flutter behavior when the available data cannot train it.
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cs.CV Zecong Tang, Zian Guan, Yuncheng Guo et al. · Oct 22, 2026

HiSTEVE tackles the challenge of building Minecraft agents that can perform long-horizon tasks using only native keyboard-and-mouse control, without relying on environment APIs or predefined skills. It proposes a hierarchical VLA agent that pairs a capability-aware harness—equipped with structured memory, a VLM planner, and a policy-coupled completion detector—with a single low-level VLA policy for visuomotor execution. The core idea is to close the loop between high-level planning and raw pixel-to-action control in a partially observable open world, which matters for developing generally capable game-playing agents.

Building virtual embodied agents that operate in open-ended games like human players is a long-standing goal requiring both long-horizon autonomy and reliable native-interface control. As a procedurally generated open world, Minecraft provides a natural testbed for studying the integration of these capabilities. Existing agents typically provide either native visuomotor control without long-horizon autonomy or high-level planning executed through environment APIs or predefined skills. To bridge this gap, we propose HiSTEVE, a hierarchical VLA agent with a capability-aware agent harness. At the orchestration level, we equip the harness with structured memory for tracking progress and a VLM planner for selecting subtasks within the VLA's capabilities. To reliably determine subtask completion, we further introduce a policy-coupled task completion state detector that conditions on VLA policy context to signal candidate completion. At the control level, a single VLA executes all subtasks with vision-only perception and native keyboard-and-mouse actions. To mitigate interference between heterogeneous GUI and non-GUI interactions, we introduce regime-specific RMSNorm branches and separate mouse-movement token embeddings. We also train the VLA through world knowledge injection, imitation learning, and reinforcement learning with environment feedback to improve reliability and recovery. HiSTEVE achieves state-of-the-art atomic-task performance, scoring 85.0% on MineStudio Bench and a 37.4% average success rate on OpenHA, while also completing long-horizon tasks such as crafting an iron pickaxe from scratch like human players.
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cs.CVcs.GR Jinyuan Mao, Zhihao Shen, Chenxi Liu · Oct 22, 2026

Fine-tuning diffusion models has yielded over 100K community adapters, but merging them interactively creates a high-dimensional, expensive black-box optimization problem: prior work requires live image generation in every round and is limited to a few dozen preselected adapters. HimmBO splits the search into a screening stage that recovers promising adapters via level-set estimation over a precomputed gallery, followed by a refinement stage that optimizes merge coefficients only within that low-dimensional active set. A style-aware Gaussian-process kernel transfers preference information between visually similar adapters, allowing the system to scale to libraries of over one thousand adapters while using under one tenth the image generations of prior work.

Fine-tuning has become a common way to customize text-to-image models, leading to community collections of over 100K lightweight adapters. Adapters sharing a base model can be merged with continuous coefficients. This turns a large collection into a high-dimensional continuous design space, which recent work explores interactively using preferential Bayesian optimization (PBO). However, existing approaches are limited to a few dozen preselected adapters and require expensive image generation in every interaction round. We introduce HimmBO, a two-stage method that scales preference-driven adapter merging to much larger collections while reducing image-generation cost. Its screening stage recovers the active adapter set through level-set estimation over pre-generated images, requiring no image generation. The refinement stage then optimizes merge coefficients in the recovered low-dimensional subspace. Both stages use a style-aware kernel, allowing preference information to transfer between visually similar adapters. In simulated-user image-matching experiments, HimmBO achieves higher final similarity than all comparisons while reaching a given similarity with under one tenth of the image generations required by prior work. Its performance remains stable as the collection grows to 1080 adapters, while competing methods degrade substantially.
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cs.CL Mustafa Omer Gul, Philippe Laban, Tanya Goyal et al. · Oct 22, 2026

Users increasingly rely on AI assistants for complex, multi-turn tasks, but evaluating these systems requires simulators that can both follow intricate intents and behave like real humans. This paper proposes UserLM-2.0, an 8B-parameter simulator trained with multi-turn reinforcement learning that jointly optimizes task fidelity and naturalness through a lightweight, dynamically retrained discriminator. By reaching $46.2\%$ conversation validity—over triple prior state-of-the-art—it demonstrates a practical path forward, though a sizable gap to real human conversations remains.

Users increasingly rely on AI systems for extended, multi-turn tasks, yet evidence indicates that LLM-based system performance degrades over prolonged interaction. To evaluate and improve AI assistants in such settings, we need user simulators that faithfully follow complex user intents while exhibiting realistic conversational behavior. Existing approaches manifest a trade-off: prompted assistants can follow complex user intents but lack behavioral fidelity, while specialized user simulators better approximate conversational behavior but struggle to remain faithful to complex intents. In this paper, we propose a reinforcement learning (RL) recipe that jointly rewards task intent adherence and behavioral naturalness. A crucial contribution of the method is operationalizing naturalness with a lightweight discriminator trained in an alternating, adversarial loop with the user simulator. We release the resulting model, UserLM-2.0, which produces valid simulated conversations (i.e., meeting both task-faithfulness and naturalness criteria) 46.2% of the time, over three times the rate of the strongest prior user simulator (14.1%).
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cs.LG Sihan Yang, Jie Huang, Hanxuan Li et al. · Oct 22, 2026

Sequence compression is a critical bottleneck in efficient language and multimodal models, yet most architectures rely on simple pooling or MLP projections that ignore inter-token correlations. This paper reframes compression as a test-time ridge regression problem: input tokens define a regression whose fitted coefficients become the compressed vector. The resulting TTR-Compressor solves exactly in closed form via a small Cholesky factorization, introduces only $2d$ learnable parameters, and yields strong gains on long-context retrieval and visual token merging.

Sequence compression is a fundamental operation and a critical information bottleneck in efficient language and multimodal models, and yet prevailing approaches based on pooling or learned projections remain underperforming. We revisit sequence compression through the lens of test-time regression: input tokens define a regression problem whose fitted coefficients form the compressed representation. Importantly, the regression problem is learned end-to-end via backpropagation, while its coefficients are computed efficiently in closed form during the forward pass. This leads to TTR-Compressor, a general alternative to conventional pooling and projection-based compression. We evaluate TTR-Compressor as the compressor for block-wise sparse attention and the visual token merger for multimodal large language models. On block-wise sparse attention, TTR-Compressor improves RULER performance over attention-based compressors by a large margin. For visual token merging, it consistently outperforms the standard MLP merger and matches its performance with 55.6% fewer visual tokens. These results establish test-time regression as an effective primitive for sequence compression in efficient language and multimodal models.
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cs.CV Xiaoting Xie, Feng Qiao, Xianwei Zhang et al. · Oct 22, 2026

Multimodal sentiment analysis fuses linguistic, acoustic, and visual signals, yet standard fusion methods entangle modality-specific and cross-modal contributions in opaque joint representations. This paper proposes I2-KAN, a multi-pathway framework that explicitly maintains intra-modal and pairwise inter-modal information in separate pathways, refines each with a Task-Decoupled Linear-Gated Denoising Bottleneck, and fuses them via a structured Kolmogorov–Arnold Network. The core motivation is that a modality's standalone predictive utility can differ sharply from its interaction-conditioned utility, and the work aims to make this reasoning traceable at pathway, feature, and functional-edge levels.

Multimodal sentiment analysis (MSA) aims to infer sentiment by integrating linguistic, acoustic, and visual information. However, many fusion methods integrate modality-specific representations and cross-modal interactions into joint representations, making it difficult to determine whether predictive utility arises from a modality itself or from its interactions with others. More fundamentally, a modality's standalone predictive utility may not faithfully reflect its interaction-conditioned predictive utility. To address this issue, we propose I$^2$-KAN, an interpretable multi-pathway framework that explicitly maintains intra-modal and pairwise inter-modal information in separate structural pathways. Each pathway is refined by a Task-Decoupled Linear-Gated Denoising Bottleneck (TDL-GDB) to learn compact and task-relevant representations, followed by structured Kolmogorov-Arnold Network fusion that retains explicit pathway associations and supports multi-level interpretation. Extensive experiments on CMU-MOSI, CMU-MOSEI, and CH-SIMS v2 demonstrate strong overall performance. Ablation and interpretability analyses consistently show across the three benchmarks that low standalone predictive utility does not necessarily imply low interaction-conditioned predictive utility: a modality that appears weak in isolation can remain informative through pairwise interactions. These findings highlight the interaction-dependent nature of multimodal utility and suggest that modality utility should be characterized from both standalone and interaction-conditioned perspectives.