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2602.11824 2026-05-12 cs.AI cs.LG

Revis: Sparse Latent Steering to Mitigate Object Hallucination in Large Vision-Language Models

Jialin Wu, Wei Shi, Han Shen, Peigui Qi, Kunsheng Tang, Zhicong Huang, Binghao Wang, Zhou Yang

AI总结 尽管大视觉语言模型(LVLMs)具备强大的能力,但常常出现物体幻觉问题。为了解决这一问题,本文提出了一种无需训练的框架REVIS,通过潜空间几何方法提取纯净的视觉信息,并在抑制发生的特定网络深度进行稀疏干预,从而有效恢复视觉信息并减少计算成本。实验表明,REVIS在标准基准上将物体幻觉率降低了约19%,同时保持了模型的通用推理能力。

Comments Accepted by ICML 2026

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英文摘要

Despite the advanced capabilities of Large Vision-Language Models (LVLMs), they frequently suffer from object hallucination. One reason is that visual features and pretrained textual representations often become intertwined in the deeper network layers. To address this, we propose REVIS, a training-free framework designed to explicitly re-activate this suppressed visual information. Rooted in latent space geometry, REVIS extracts the pure visual information vector via orthogonal projection and employs a calibrated strategy to perform sparse intervention only at the precise depth where suppression occurs. This surgical approach effectively restores visual information with minimal computational cost. Empirical evaluations on standard benchmarks demonstrate that REVIS reduces object hallucination rates by approximately 19% compared to state-of-the-art baselines, while preserving general reasoning capabilities.

2602.11181 2026-05-12 cs.CL

Code Mixologist : A Practitioner's Guide to Building Code-Mixed LLMs

Himanshu Gupta, Pratik Jayarao, Chaitanya Dwivedi, Neeraj Varshney

AI总结 本文探讨了代码混合(Code-Mixing)和代码转换(Code-Switching)在大型语言模型(LLMs)中的挑战,指出尽管多语言建模取得进展,但模型在混合语言场景下仍存在语法、事实性和安全性方面的系统性退化。研究提出了一个统一的分类体系,涵盖数据、建模和评估等多个维度,并总结出一套实用指南,帮助构建和评估具备代码混合能力的LLMs。同时,文章分析了当前评估方法的不足,指出了现有基准的局限性,并探讨了代码混合可能被用于绕过模型安全机制等新兴安全问题。

Comments 8 pages main paper, 13 pages total

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英文摘要

Code-mixing and code-switching (CSW) remain challenging phenomena for large language models (LLMs). Despite recent advances in multilingual modeling, LLMs often struggle in mixed-language settings, exhibiting systematic degradation in grammaticality, factuality, and safety behavior. This work provides a comprehensive overview of CSW research in modern large language model settings. We introduce a unifying taxonomy that organizes prior work along dimensions of data, modeling, and evaluation, and we distill these findings into a practical playbook of actionable recommendations for building, adapting, and evaluating CSW-capable LLMs. We review modeling approaches ranging from CSW-tailored pre-training and task-specific post-training to prompting strategies and in-context learning. We analyze current evaluation practices, highlighting sources of instability and limited reproducibility, and we catalog existing benchmarks while critically examining their linguistic coverage and English-centric biases. Finally, we discuss emerging safety concerns, including use of code-mixing as a mechanism for bypassing model safeguards, and identify open research challenges.

2602.10356 2026-05-12 cs.CL

Autonomous Continual Learning for Environment Adaptation of Computer-Use Agents

Tianci Xue, Zeyi Liao, Tianneng Shi, Zilu Wang, Kai Zhang, Dawn Song, Yu Su, Huan Sun

AI总结 本文研究了计算机使用代理(CUA)在高度多样和动态的现实数字环境中持续学习适应的问题,核心挑战在于如何在无需人工标注数据的情况下获得高质量的训练数据。为此,作者提出了ACuRL框架,通过自主课程强化学习实现零人工数据下的持续环境适应,结合任务生成器和自动评估器CUAJudge,有效提升了代理在环境内和跨环境中的学习性能,并在多个任务上取得了显著的性能提升。

Comments 28 pages, 10 figures

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英文摘要

Real-world digital environments are highly diverse and dynamic. These characteristics cause agents to frequently encounter unseen environments and distribution shifts, making continual learning in such environments essential for computer-use agents (CUAs). However, a key challenge lies in obtaining high-quality and environment-grounded training data without relying on costly human annotation. In this work, we introduce ACuRL, an Autonomous Curriculum Reinforcement Learning framework that continually adapts agents to specific environments with zero human data. The agent first explores an environment to acquire initial experiences. During subsequent iterative training, a curriculum task generator leverages these experiences together with feedback from the previous iteration to synthesize new tasks tailored for the agent's current capabilities. To provide reliable reward signals, we introduce CUAJudge, a robust automatic evaluator for CUAs that achieves 93% agreement with human judgments. Empirically, our method effectively enables both intra-environment and cross-environment continual learning, yielding 3-29% absolute performance gains on the target environments without catastrophic forgetting on others. We also show that it can mitigate performance degradation under environment changes (e.g., version updates, platform migration, and resolution shifts). Further analyses show highly sparse updates (e.g., only 20% parameters), which helps explain the effective and robust adaptation.

2602.09534 2026-05-12 cs.CV

AUHead: Realistic Emotional Talking Head Generation via Action Units Control

Jiayi Lyu, Leigang Qu, Wenjing Zhang, Hanyu Jiang, Kai Liu, Zhenglin Zhou, Xiaobo Xia, Jian Xue, Tat-Seng Chua

AI总结 本文提出了一种名为 AUHead 的新方法,用于生成具有真实情感表达的说话人视频。该方法通过解耦音频与细粒度情感单元(Action Units, AUs)的控制,实现了对情绪表达的精确调控。研究采用两阶段框架,第一阶段利用大语言模型生成 AUs 序列,第二阶段基于 AUs 驱动的扩散模型生成高质量的视频,有效提升了情感真实性和视觉一致性。

Comments https://openreview.net/forum?id=dmzlAUkulz&referrer=%5BAuthor%20Console%5D(%2Fgroup%3Fid%3DICLR.cc%2F2026%2FConference%2FAuthors%23your-submissions) Accepted at the 14th International Conference on Learning Representations (ICLR 2026)

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英文摘要

Realistic talking-head video generation is critical for virtual avatars, film production, and interactive systems. Current methods struggle with nuanced emotional expressions due to the lack of fine-grained emotion control. To address this issue, we introduce a novel two-stage method (AUHead) to disentangle fine-grained emotion control, i.e. , Action Units (AUs), from audio and achieve controllable generation. In the first stage, we explore the AU generation abilities of large audio-language models (ALMs), by spatial-temporal AU tokenization and an "emotion-then-AU" chain-of-thought mechanism. It aims to disentangle AUs from raw speech, effectively capturing subtle emotional cues. In the second stage, we propose an AU-driven controllable diffusion model that synthesizes realistic talking-head videos conditioned on AU sequences. Specifically, we first map the AU sequences into the structured 2D facial representation to enhance spatial fidelity, and then model the AU-vision interaction within cross-attention modules. To achieve flexible AU-quality trade-off control, we introduce an AU disentanglement guidance strategy during inference, further refining the emotional expressiveness and identity consistency of the generated videos. Results on benchmark datasets demonstrate that our approach achieves competitive performance in emotional realism, accurate lip synchronization, and visual coherence, significantly surpassing existing techniques. Our implementation is available at https://github.com/laura990501/AUHead_ICLR

2602.09016 2026-05-12 cs.CV

Raster2Seq: Polygon Sequence Generation for Floorplan Reconstruction

Hao Phung, Hadar Averbuch-Elor

AI总结 本文提出了一种名为 Raster2Seq 的方法,用于从栅格化的平面图图像中重建结构化的矢量图形表示。该方法将平面图重建视为序列到序列的任务,将房间、窗户和门等元素表示为包含几何和语义信息的带标签多边形序列。通过引入基于可学习锚点的自回归解码器,模型能够根据图像特征和已生成的顶点预测下一个顶点,从而更有效地生成复杂且具有多样多边形结构的平面图。实验表明,该方法在多个标准数据集上取得了最先进的性能,并在更具挑战性的数据集上也表现出良好的泛化能力。

Comments Accepted to SIGGRAPH 2026. Project page: https://cornell-vailab.github.io/Raster2Seq/

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英文摘要

Reconstructing a structured vector-graphics representation from a rasterized floorplan image is typically an important prerequisite for computational tasks involving floorplans such as automated understanding or CAD workflows. However, existing techniques struggle in faithfully generating the structure and semantics conveyed by complex floorplans that depict large indoor spaces with many rooms and a varying numbers of polygon corners. To this end, we propose Raster2Seq, framing floorplan reconstruction as a sequence-to-sequence task in which floorplan elements--such as rooms, windows, and doors--are represented as labeled polygon sequences that jointly encode geometry and semantics. Our approach introduces an autoregressive decoder that learns to predict the next corner conditioned on image features and previously generated corners using guidance from learnable anchors. These anchors represent spatial coordinates in image space, hence allowing for effectively directing the attention mechanism to focus on informative image regions. By embracing the autoregressive mechanism, our method offers flexibility in the output format, enabling for efficiently handling complex floorplans with numerous rooms and diverse polygon structures. Our method achieves state-of-the-art performance on standard benchmarks such as Structure3D, CubiCasa5K, and Raster2Graph, while also demonstrating strong generalization to more challenging datasets like WAFFLE, which contain diverse room structures and complex geometric variations.

2602.06733 2026-05-12 cs.LG cs.AI cs.MA

Pairwise is Not Enough: Hypergraph Neural Networks for Multi-Agent Pathfinding

Rishabh Jain, Keisuke Okumura, Michael Amir, Pietro Lio, Amanda Prorok

AI总结 多智能体路径规划(MAPF)是一个典型的多智能体协作问题,要求多个智能体在不发生碰撞的情况下分别到达目标位置。现有基于图神经网络(GNN)的方法通常仅限于两两之间的信息传递,难以有效捕捉多智能体之间的高阶交互,导致在密集环境中表现不佳。为此,本文提出了一种新的超图注意力网络 HMAGAT,通过有向超图上的注意力机制显式建模群体动态,有效缓解了注意力稀释问题,并在更少的训练数据和更少参数的情况下取得了优于现有最优方法的性能。

Comments Published at ICLR 2026

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英文摘要

Multi-Agent Path Finding (MAPF) is a representative multi-agent coordination problem, where multiple agents are required to navigate to their respective goals without collisions. Solving MAPF optimally is known to be NP-hard, leading to the adoption of learning-based approaches to alleviate the online computational burden. Prevailing approaches, such as Graph Neural Networks (GNNs), are typically constrained to pairwise message passing between agents. However, this limitation leads to suboptimal behaviours and critical issues, such as attention dilution, particularly in dense environments where group (i.e. beyond just two agents) coordination is most critical. Despite the importance of such higher-order interactions, existing approaches have not been able to fully explore them. To address this representational bottleneck, we introduce HMAGAT (Hypergraph Multi-Agent Attention Network), a novel architecture that leverages attentional mechanisms over directed hypergraphs to explicitly capture group dynamics. Empirically, HMAGAT establishes a new state-of-the-art among learning-based MAPF solvers: e.g., despite having just 1M parameters and being trained on 100$\times$ less data, it outperforms the current SoTA 85M parameter model. Through detailed analysis of HMAGAT's attention values, we demonstrate how hypergraph representations mitigate the attention dilution inherent in GNNs and capture complex interactions where pairwise methods fail. Our results illustrate that appropriate inductive biases are often more critical than the training data size or sheer parameter count for multi-agent problems.

2602.06382 2026-05-12 cs.RO

Now You See That: Learning End-to-End Humanoid Locomotion from Raw Pixels

Wandong Sun, Yongbo Su, Leoric Huang, Alex Zhang, Dwyane Wei, Mu San, Daniel Tian, Ellie Cao, Baoshi Cao, Yang Liu, Finn Yan, Ethan Xie, Zongwu Xie

AI总结 该研究旨在解决基于视觉的人形机器人行走任务中面临的仿真到现实的迁移难题和复杂地形适应问题。为应对感知噪声和多地形学习目标冲突的挑战,作者提出了一种端到端的视觉驱动框架,包含高保真深度传感器仿真和视觉感知行为蒸馏方法,以提升现实环境中的鲁棒性;同时引入地形特定的奖励塑造与多评判器学习机制,增强机器人在不同地形下的适应能力。实验表明,该方法在多种人形机器人平台上表现出优异的通用性和应对复杂任务的能力。

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英文摘要

Achieving robust vision-based humanoid locomotion remains challenging due to two fundamental issues: the sim-to-real gap introduces significant perception noise that degrades performance on fine-grained tasks, and training a unified policy across diverse terrains is hindered by conflicting learning objectives. To address these challenges, we present an end-to-end framework for vision-driven humanoid locomotion. For robust sim-to-real transfer, we develop a high-fidelity depth sensor simulation that captures stereo matching artifacts and calibration uncertainties inherent in real-world sensing. We further propose a vision-aware behavior distillation approach that combines latent space alignment with noise-invariant auxiliary tasks, enabling effective knowledge transfer from privileged height maps to noisy depth observations. For versatile terrain adaptation, we introduce terrain-specific reward shaping integrated with multi-critic and multi-discriminator learning, where dedicated networks capture the distinct dynamics and motion priors of each terrain type. We validate our approach on two humanoid platforms equipped with different stereo depth cameras. The resulting policy demonstrates robust performance across diverse environments, seamlessly handling extreme challenges such as high platforms and wide gaps, as well as fine-grained tasks including bidirectional long-term staircase traversal.

2602.05946 2026-05-12 cs.LG stat.ML

f-GRPO and Beyond: Divergence-Based Reinforcement Learning Algorithms for General LLM Alignment

Rajdeep Haldar, Lantao Mei, Guang Lin, Yue Xing, Qifan Song

AI总结 本文研究了如何通过基于散度的强化学习算法实现大语言模型的一般对齐,包括基于可验证奖励的强化学习(RLVR)等场景。作者提出了 $f$-GRPO 和 $f$-HAL 两种方法,分别用于基于策略的奖励优化和结合策略与偏好监督的混合对齐损失,证明了它们能够估计奖励对齐与不对齐分布之间的 $f$-散度,并在实验中展示了其在数学推理任务和安全对齐中的优越性。

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英文摘要

Recent work shows that preference alignment objectives can be interpreted as divergence estimators between aligned (preferred) & unaligned (less-preferred) distributions, yielding a principled recipe for designing alignment losses. However, this view has so far been limited to preference-based supervision. We extend it to general LLM alignment, including reinforcement learning with verifiable rewards (RLVR), where alignment feedback is given only as scalar rewards. We introduce $f$-Group Relative Policy Optimization ($f$-GRPO), a class of on-policy RL objectives, and $f$-Hybrid Alignment Loss ($f$-HAL), which combines on-policy reward optimization with off-policy preference supervision. We show that these objectives estimate $f$-divergences between reward-aligned & reward-unaligned distributions induced by above- & below-average reward responses, and prove expected reward improvement after alignment. Empirically, $f$-GRPO improves over GRPO on math-reasoning RLVR tasks, while hybrid $f$-HAL mitigates reward hacking in on-policy safety alignment when verifiable rewards are unavailable and learned reward models must be used.

2602.05243 2026-05-12 cs.LG cs.CV

CORP: Closed-Form One-shot Representation-Preserving Structured Pruning for Transformers

Boxiang Zhang, Baijian Yang

AI总结 本文提出CORP,一种无需梯度或微调的闭式单次结构化剪枝方法,用于在Transformer模型中去除多层感知机和注意力子结构。该方法将结构化剪枝建模为表示恢复问题,通过闭式岭回归推导出补偿模型权重的解析解,从而在保持高精度的前提下实现模型的高效压缩。实验表明,CORP在ImageNet数据集上对DeiT模型进行大量剪枝后仍能保持较高的分类准确率。

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英文摘要

Transformers achieve strong accuracy but incur high compute and memory cost. Structured pruning reduces inference cost, but most methods rely on retraining or multi-stage optimization, which limits post-training deployment. We propose CORP, a closed-form one-shot structured pruning method that removes MLP dimensions and attention substructures using only unlabeled calibration data without gradients or fine-tuning. CORP formulates structured pruning as a representation recovery problem. It models removed components as affine functions of retained components and derives closed-form ridge regression solutions that fold compensation into model weights. This minimizes a layer-local affine/logit reconstruction objective under the calibration distribution. Experiments on ImageNet with DeiT reveal strong redundancy in both MLP and attention representations. With CORP, models retain high accuracy under aggressive sparsity. On DeiT-Huge, CORP achieves 83.27% Top-1 accuracy after pruning 50\% of both MLP and attention structures.

2602.05214 2026-05-12 cs.LG

Disentangled Representation Learning via Flow Matching

Jinjin Chi, Taoping Liu, Mengtao Yin, Ximing Li, Yongcheng Jing, Jialie Shen, Leszek Rutkowski, Dacheng Tao

AI总结 本文提出了一种基于流匹配的解耦表征学习框架,将解耦问题转化为在紧凑潜在空间中学习条件流的过程。为实现显式的语义对齐,作者引入了一个非重叠正则化项,以抑制不同因素间的干扰并减少信息泄露。实验表明,该方法在多个数据集上均优于现有基线,取得了更高的解耦度评分以及更好的可控性和样本保真度。

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英文摘要

Disentangled representation learning aims to capture the underlying explanatory factors of observed data, enabling a principled understanding of the data-generating process. Recent advances in generative modeling have introduced new paradigms for learning such representations. However, existing diffusion-based methods encourage factor independence via inductive biases, yet frequently lack strong semantic alignment. In this work, we propose a flow matching-based framework for disentangled representation learning, which casts disentanglement as learning factor-conditioned flows in a compact latent space. To enforce explicit semantic alignment, we introduce a non-overlap (orthogonality) regularizer that suppresses cross-factor interference and reduces information leakage between factors. Extensive experiments across multiple datasets demonstrate consistent improvements over representative baselines, yielding higher disentanglement scores as well as improved controllability and sample fidelity.

2602.03916 2026-05-12 cs.CV cs.CE cs.CL cs.LG

SpatiaLab: Can Vision-Language Models Perform Spatial Reasoning in the Wild?

Azmine Toushik Wasi, Wahid Faisal, Abdur Rahman, Mahfuz Ahmed Anik, Munem Shahriar, Mohsin Mahmud Topu, Sadia Tasnim Meem, Rahatun Nesa Priti, Sabrina Afroz Mitu, Md. Iqramul Hoque, Shahriyar Zaman Ridoy, Mohammed Eunus Ali, Majd Hawasly, Mohammad Raza, Md Rizwan Parvez

AI总结 SpatiaLab 是一个用于评估视觉语言模型(VLMs)在真实场景中空间推理能力的综合性基准。该研究指出,现有模型在处理复杂的空间关系、深度感知、导航和三维几何等问题时仍存在显著不足。SpatiaLab 包含 1400 个视觉问答对,涵盖六个主要类别及 30 种任务类型,实验表明当前最先进的 VLMs 在空间推理任务上的表现远低于人类。

Comments Accepted to ICLR 2026 (https://openreview.net/forum?id=fWWUPOb0CT). 92 Pages. 42 Figures and 29 Tables

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Journal ref
ICLR 2026
英文摘要

Spatial reasoning is a fundamental aspect of human cognition, yet it remains a major challenge for contemporary vision-language models (VLMs). Prior work largely relied on synthetic or LLM-generated environments with limited task designs and puzzle-like setups, failing to capture the real-world complexity, visual noise, and diverse spatial relationships that VLMs encounter. To address this, we introduce SpatiaLab, a comprehensive benchmark for evaluating VLMs' spatial reasoning in realistic, unconstrained contexts. SpatiaLab comprises 1,400 visual question-answer pairs across six major categories: Relative Positioning, Depth & Occlusion, Orientation, Size & Scale, Spatial Navigation, and 3D Geometry, each with five subcategories, yielding 30 distinct task types. Each subcategory contains at least 25 questions, and each main category includes at least 200 questions, supporting both multiple-choice and open-ended evaluation. Experiments across diverse state-of-the-art VLMs, including open- and closed-source models, reasoning-focused, and specialized spatial reasoning models, reveal a substantial gap in spatial reasoning capabilities compared with humans. In the multiple-choice setup, InternVL3.5-72B achieves 54.93% accuracy versus 87.57% for humans. In the open-ended setting, all models show a performance drop of around 10-25%, with GPT-5-mini scoring highest at 40.93% versus 64.93% for humans. These results highlight key limitations in handling complex spatial relationships, depth perception, navigation, and 3D geometry. By providing a diverse, real-world evaluation framework, SpatiaLab exposes critical challenges and opportunities for advancing VLMs' spatial reasoning, offering a benchmark to guide future research toward robust, human-aligned spatial understanding. SpatiaLab is available at: https://spatialab-reasoning.github.io/.

2602.03783 2026-05-12 cs.LG cs.AI cs.CL

Efficient Estimation of Kernel Surrogate Models for Task Attribution

Zhenshuo Zhang, Minxuan Duan, Hongyang R. Zhang

AI总结 本文研究如何量化不同训练任务对目标任务性能的影响,即任务归因问题。传统方法如留一法重新训练计算开销大,而现有线性代理模型无法捕捉非线性任务交互。为此,作者提出基于核方法的代理模型,能够更有效地表示二阶任务交互,并设计了一种基于梯度的高效估计方法,无需重复训练即可获得高精度的代理模型。实验表明,核代理模型在多个任务场景中显著优于线性模型和影响函数方法,提升了任务归因的准确性和可扩展性。

Comments 27 pages. Appeared in ICLR 2026

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英文摘要

Modern AI agents such as large language models are trained on diverse tasks -- translation, code generation, mathematical reasoning, and text prediction -- simultaneously. A key question is how to quantify the influence of each individual training task on performance on a target task, a problem we refer to as task attribution. The direct approach, leave-one-out retraining, measures the effect of removing each task, but is computationally infeasible at scale. An alternative approach that builds surrogate models to predict the performance on a target task for any subset of training tasks has emerged in the recent literature. Prior work focuses on linear surrogate models, which capture first-order relationships but miss nonlinear interactions such as XOR-type effects. In this paper, we first consider a unified task-weighting framework for analyzing task-attribution methods and establish a new connection between linear surrogate models and influence functions via a second-order analysis. Then, we introduce kernel surrogate models, which more effectively represent second-order task interactions. To efficiently learn the kernel surrogate, we develop a gradient-based estimation procedure that leverages a first-order approximation of pretrained models; empirically, this yields accurate surrogate estimates with less than $2\%$ relative error without repeated retraining. Experiments across multiple settings -- including mathematical reasoning in transformers, in-context learning, and multi-objective reinforcement learning -- demonstrate the effectiveness of kernel surrogate models. They achieve a $25\%$ higher correlation with the leave-one-out ground truth than linear surrogates and influence-function baselines, enabling more accurate and scalable task attribution. When used for downstream data selection, kernel surrogate models further yield a $40\%$ improvement in the aforementioned settings.

2602.01687 2026-05-12 cs.CL cs.AI

Functional Subspace, where language models can use vector algebra to solve problems

Jung H. Lee, Sujith Vijayan

AI总结 该研究探讨了大型语言模型(LLMs)在执行任务时是否利用子空间和向量代数进行操作。研究通过分析模型在上下文学习中的功能模块和残差流,发现LLMs能够创建子空间以积累证据,并通过简单的代数运算在这些子空间中解决任务。这一发现为理解LLMs的工作机制和潜在能力提供了新的视角。

Comments page 20, 7 main figures, 8 supplementary figures

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英文摘要

Large language models (LLMs) were invented for natural language tasks such as translation, but they have proved that they can perform highly complex functions across domains. Additionally, they have been thought to develop new skills without being trained on them. These learning capabilities lead to LLMs adoption in a wide range of domains. Thus, it is imperative that we understand their operating mechanisms and limitations for proper diagnostics and repair. The earlier studies proposed that high level concepts are encoded as linear directions in LLMs activation space and that the geometry of embeddings have semantic meanings. Inspired by these studies, we hypothesize that LLMs may use subspaces and vector algebra in subspaces to perform tasks. To address this hypothesis, we analyze LLMs' functional modules and residual streams collected from LLMs engaging in in-context learning (ICL), one of the emergent abilities. Our analyses suggest that 1) LLMs can create subspaces, where evidence can be accumulated and 2) ICL tasks can be solved via simple algebraic operations in subspaces.

2602.00986 2026-05-12 cs.CL

Sparse Reward Subsystem in Large Language Models

Guowei Xu, Mert Yuksekgonul, James Zou

AI总结 近期研究表明,大语言模型的隐藏状态中编码了与奖励相关的信息,如答案正确性和模型置信度。本文发现这些信息主要集中在隐藏状态中一小部分神经元上,并通过简单探针识别出两类神经元:价值神经元和多巴胺神经元,分别编码状态价值和时间差分误差。这一发现揭示了大语言模型中存在一个稀疏的奖励子系统,为理解模型内部奖励机制提供了新的视角,并展示了其在模型置信度预测和推理搜索引导中的应用。

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英文摘要

Recent studies show that LLM hidden states encode reward-related information, such as answer correctness and model confidence. However, existing approaches typically fit black-box probes on the full hidden states, offering little insight into how this information is structured across neurons. In this paper, we show that reward-related information is concentrated in a sparse subset of neurons. Using simple probing, we identify two types of neurons: value neurons, whose activations predict state value, and dopamine neurons, whose activations encode step-level temporal difference (TD) errors. Together, these neurons form a sparse reward subsystem within LLM hidden states. These names are drawn by analogy with neuroscience, where value neurons and dopamine neurons in the biological reward subsystem also encode value and reward prediction errors, respectively. We demonstrate that value neurons are robust and transferable across diverse datasets and models, and provide causal evidence that they encode reward-related information. Finally, we show applications of the reward subsystem: value neurons serve as effective predictors of model confidence, and dopamine neurons can function as a process reward model (PRM) to guide inference-time search.

2602.00953 2026-05-12 cs.LG

SAGE: Agentic Framework for Interpretable and Clinically Translatable Computational Pathology Biomarker Discovery

Sahar Almahfouz Nasser, Juan Francisco Pesantez Borja, Jincheng Liu, Sandeep Manandhar, Shikhar Shiromani, Mohammad Tanvir Hasan, Zenghan Wang, Suman Ghosh, Jinchu Li, Xuejian Xu, Aniket Ramkrishnan Iyer, Naoto Tokuyama, Twisha Shah, Tilak Pathak, Soundharya Kumaresan, Yohei Abe, Himanshu Maurya, Anant Madabhushi

AI总结 SAGE 是一种用于可解释且具有临床转化潜力的计算病理学生物标志物发现的智能代理框架。该方法通过知识图谱引导的假设生成、基于辩论的多代理新颖性评估以及端到端的自动化验证流程,将生物标志物的发现过程建立在坚实的生物学证据之上。研究的核心贡献在于将原本依赖直觉和文献浏览的标志物发现过程转化为结构化、可追溯的推理流程,从而提升其临床可信度和可应用性。

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英文摘要

Engineered image-based biomarkers offer a clinically interpretable alternative to black-box AI in computational pathology, yet their discovery remains largely intuition-driven, guided by fragmented literature rather than rigorous biological validation. We introduce SAGE (Structured Agentic system for hypothesis Generation and Evaluation), a multi-agent framework that grounds biomarker discovery in biological evidence through three mechanisms: (i) knowledge-graph-anchored hypothesis generation via multi-path ontological reasoning, (ii) a debate-based multi-agent novelty assessment that stress-tests candidate biomarkers against existing literature, and (iii) an end-to-end automated validation pipeline that translates hypotheses directly into executable analyses on multimodal pathology datasets. Together, these components shift biomarker discovery from an intuition-driven, literature-browsing exercise into a structured, traceable reasoning process that clinicians and researchers can inspect, trust, and build upon.

2602.00877 2026-05-12 cs.RO

Learning When to Jump for Off-road Navigation

Zhipeng Zhao, Taimeng Fu, Shaoshu Su, Qiwei Du, Ehsan Tarkesh Esfahani, Karthik Dantu, Souma Chowdhury, Chen Wang

AI总结 本文研究了越野导航中如何通过控制速度实现安全跳跃以克服障碍的问题。为了解决现有方法忽视运动动态特性的不足,作者提出了基于运动感知的可通行性(MAT)表示方法,将地形代价建模为速度的高斯函数。该方法通过感知预测地形参数,并在规划过程中高效更新不同速度下的地形代价,从而实现敏捷的越野导航。实验表明,MAT在保证安全性的前提下显著提升了导航性能,减少了75%的路径绕行。

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英文摘要

Low speed does not always guarantee safety in off-road driving. For instance, crossing a ditch may be risky at a low speed due to the risk of getting stuck, yet safe at a higher speed with a controlled, accelerated jump. Achieving such behavior requires path planning that explicitly models complex motion dynamics, whereas existing methods often neglect this aspect and plan solely based on positions or a fixed velocity. To address this gap, we introduce Motion-aware Traversability (MAT) representation to explicitly model terrain cost conditioned on actual robot motion. Instead of assigning a single scalar score for traversability, MAT models each terrain region as a Gaussian function of velocity. During online planning, we decompose the terrain cost computation into two stages: (1) predict terrain-dependent Gaussian parameters from perception in a single forward pass, (2) efficiently update terrain costs for new velocities inferred from current dynamics by evaluating these functions without repeated inference. We develop a system that integrates MAT to enable agile off-road navigation and evaluate it in both simulated and real-world environments with various obstacles. Results show that MAT achieves real-time efficiency and enhances the performance of off-road navigation, reducing path detours by 75% while maintaining safety across challenging terrains.

2602.00678 2026-05-12 cs.RO

Toward Reliable Sim-to-Real Predictability for MoE-based Robust Quadrupedal Locomotion

Tianyang Wu, Hanwei Guo, Yuhang Wang, Junshu Yang, Xinyang Sui, Jiayi Xie, Xingyu Chen, Zeyang Liu, Xuguang Lan

AI总结 该研究旨在解决基于混合专家(MoE)架构的四足机器人在复杂地形中从仿真到现实的可靠迁移问题。研究提出了一种统一框架,结合了鲁棒多地形表示的MoE运动策略和用于评估仿真到现实迁移能力的RoboGauge预测评估系统。通过仅依靠本体感觉信息,该方法在多种未知复杂地形中实现了稳定且高效的运动,并在高速测试中达到了4米/秒的速度,展示了其优越的性能和泛化能力。

Comments Accepted at Robotics Science and Systems (RSS), 2026. Project Page: https://robogauge.github.io/complete/

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英文摘要

Reinforcement learning has shown strong promise for quadrupedal agile locomotion, even with proprioception-only sensing. In practice, however, sim-to-real gap and reward overfitting in complex terrains can produce policies that fail to transfer, while physical validation remains risky and inefficient. To address these challenges, we introduce a unified framework encompassing a Mixture-of-Experts (MoE) locomotion policy for robust multi-terrain representation with RoboGauge, a predictive assessment suite that quantifies sim-to-real transferability. The MoE policy employs a gated set of specialist experts to decompose latent terrain and command modeling, achieving superior deployment robustness and generalization via proprioception alone. RoboGauge further provides multi-dimensional proprioception-based metrics via sim-to-sim tests over terrains, difficulty levels, and domain randomizations, enabling reliable MoE policy selection without extensive physical trials. Experiments on a Unitree Go2 demonstrate robust locomotion on unseen challenging terrains, including snow, sand, stairs, slopes, and 30 cm obstacles. In dedicated high-speed tests, the robot reaches 4 m/s and exhibits an emergent narrow-width gait associated with improved stability at high velocity.

2602.00318 2026-05-12 cs.LG cs.AI cs.CR

Optimal Transport-Guided Adversarial Attacks on Graph Neural Network-Based Bot Detection

Kunal Mukherjee, Zulfikar Alom, Tran Gia Bao Ngo, Cuneyt Gurcan Akcora, Murat Kantarcioglu

AI总结 随着社交媒体上机器人账户的增多,基于图神经网络(GNN)的机器人检测方法受到越来越多关注。然而,现有攻击方法在面对现实场景中的领域特定和时间约束时效果有限。为此,本文提出BOCLOAK方法,通过结合最优运输理论,系统评估GNN在边编辑和节点注入攻击下的鲁棒性,并在满足现实约束条件下实现高效的攻击,显著提升了攻击成功率,同时大幅降低了计算资源消耗,为对抗攻击与现实机器人检测之间的桥梁提供了轻量且原理清晰的框架。

Comments Accepted to Proceedings of the Forty-Third International Conference on Machine Learning (ICML) 2026

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Journal ref
Proceedings of the Forty-Third International Conference on Machine Learning 2026
英文摘要

The rise of bot accounts on social media poses significant risks to public discourse. To address this threat, modern bot detectors increasingly rely on Graph Neural Networks (GNNs). However, the effectiveness of these GNN-based detectors in real-world settings remains poorly understood. In practice, attackers continuously adapt their strategies as well as must operate under domain-specific and temporal constraints, which can fundamentally limit the applicability of existing attack methods. As a result, there is a critical need for robust GNN-based bot detection methods under realistic, constraint-aware attack scenarios. To address this gap, we introduce BOCLOAK to systematically evaluate the robustness of GNN-based social bot detection via both edge editing and node injection adversarial attacks under realistic constraints. BOCLOAK constructs a probability measure over spatio-temporal neighbor features and learns an optimal transport geometry that separates human and bot behaviors. It then decodes transport plans into sparse, plausible edge edits that evade detection while obeying real-world constraints. We evaluate BOCLOAK across three social bot datasets, five state-of-the-art bot detectors, three adversarial defenses, and compare it against four leading graph adversarial attack baselines. BOCLOAK achieves up to 80.13% higher attack success rates while using 99.80% less GPU memory under realistic real-world constraints. Most importantly, BOCLOAK shows that optimal transport provides a lightweight, principled framework for bridging the gap between adversarial attacks and real-world bot detection.

2601.23273 2026-05-12 cs.CL

UPA: Unsupervised Prompt Agent via Tree-Based Search and Selection

Siran Peng, Weisong Zhao, Tianyu Fu, Chenxu Zhao, Tianshuo Zhang, Haoyuan Zhang, Xiangyu Zhu, Minghui Wu, Zhen Lei

AI总结 本文提出了一种无需监督奖励信号的提示优化方法UPA,通过树结构搜索与选择实现结构化提示空间的探索。UPA利用大型语言模型进行细粒度、位置偏差校正的成对比较,结合基于Bradley-Terry-Luce模型的两阶段框架,分别进行局部比较的贝叶斯聚合与全局竞赛式比较,从而在无监督环境下有效识别最优提示。实验表明,UPA在多个任务中优于现有方法,验证了其在无监督场景下的有效性。

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英文摘要

Prompt agents have recently emerged as a promising paradigm for automated prompt optimization, framing prompt discovery as a sequential decision-making problem over a structured prompt space. While this formulation enables the use of advanced planning algorithms, these methods typically assume access to supervised reward signals, which are often unavailable in practical scenarios. In this work, we propose UPA, an Unsupervised Prompt Agent that realizes structured search and selection without relying on ground-truth (GT) rewards. Specifically, during search, UPA iteratively constructs an evolving tree structure to navigate the prompt space, guided by fine-grained and position-debiased pairwise comparisons from Large Language Models (LLMs). Crucially, as these local comparisons do not inherently yield a consistent global scale, we decouple systematic prompt exploration from final selection, introducing a two-stage framework grounded in the Bradley-Terry-Luce (BTL) model. This framework first performs path-wise Bayesian aggregation of local comparisons to filter candidates under uncertainty, followed by global tournament-style comparisons to infer latent prompt quality and identify the optimal prompt. Experiments across multiple tasks demonstrate that UPA consistently outperforms existing prompt optimization methods, showing that agent-style optimization can remain highly effective even in unsupervised settings.

2601.22320 2026-05-12 cs.LG stat.ML

Matrix Factorization for Practical Continual Mean Estimation Under User-Level Differential Privacy

Nikita P. Kalinin, Ali Najar, Valentin Roth, Christoph H. Lampert

AI总结 本文研究了在用户级差分隐私保护下的连续均值估计问题,即在数据向量依次到达的情况下,如何持续准确地估计累积均值。为了解决这一问题,作者采用近似差分隐私框架,并结合矩阵分解机制,提出了一种专门用于均值估计的矩阵分解方法,该方法在保证隐私的同时,能够显著降低均值估计的均方误差,提升了实际应用中的估计精度与效率。

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英文摘要

We study continual mean estimation, where data vectors arrive sequentially and the goal is to maintain accurate estimates of the running mean. We address this problem under user-level differential privacy, which protects each user's entire dataset even when they contribute multiple data points. Previous work on this problem has focused on pure differential privacy. While important, this approach limits applicability, as it leads to overly noisy estimates. In contrast, we analyze the problem under approximate differential privacy, adopting recent advances in the Matrix Factorization mechanism. We introduce a novel mean estimation specific factorization, which is both efficient and accurate, achieving asymptotically lower mean-squared error bounds in continual mean estimation under user-level differential privacy.

2601.21699 2026-05-12 cs.CL

Can David Beat Goliath? On Multi-Hop Reasoning with Resource-Constrained Agents

Hojae Han, Heeyun Jung, Jongyoon Kim, Seung-won Hwang

AI总结 本文研究了在资源受限条件下,如何提升多跳推理代理的训练效率与效果。作者提出了一种名为 David-GRPO 的新方法,通过引入专家引导和证据引导的探索策略,有效利用小批量数据进行强化学习,从而提高推理深度和证据覆盖度。实验表明,在相同低预算条件下,该方法在多个多跳问答基准测试中优于现有强化学习基线。

Comments Preprint

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英文摘要

Multi-turn reasoning agents solve complex questions by decomposing them into intermediate retrieval or tool-use steps, for accumulating supporting evidence across turns. Meanwhile, with reinforcement learning (RL), training these agents rely on many on-policy rollouts and large training batches. Under realistic resource constraints that make dense exploration infeasible, each RL batch contains only few useful reasoning paths from the current policy. Existing approaches do not fully address this bottleneck: SFT-based initialization can overfit when annotated trajectories are scarce, retrieval-level rewards can assign credit to individual retrieved documents without directly optimizing coverage of the full evidence set, and expansion can waste rollouts from poorly chosen prefixes. We introduce David-GRPO, which improves small-batch learning by using information from both outside and inside the current policy: (i) expert bootstrapping injects a few off-policy expert trajectories into RL updates, and (ii) evidence-guided exploration turns on-policy partial successes into evidence-coverage scores and additional continuations. On agents up to 1.5B parameters trained on four RTX 3090 GPUs, David-GRPO improves over prior RL baselines under the same low-budget setting on six multi-hop QA benchmarks. The gains come with a behavioral shift: unlike prior low-budget RL baselines that often skip retrieval or stop after shallow search, David-GRPO learns to increase retrieval depth and evidence coverage.

2601.18823 2026-05-12 cs.LG

VAE with Hyperspherical Coordinates: Improving Anomaly Detection from Hypervolume-Compressed Latent Space

Alejandro Ascarate, Leo Lebrat, Rodrigo Santa Cruz, Clinton Fookes, Olivier Salvado

AI总结 本文研究了如何通过引入超球坐标系改进变分自编码器(VAE)在异常检测中的性能。传统VAE在高维潜在空间中难以有效检测异常,因为潜在向量倾向于分布在超球体的“赤道”区域,导致检测困难。作者提出将潜在变量表示为超球坐标,从而压缩潜在空间体积并增强后验分布的表达能力,最终在多个真实世界和标准数据集上显著提升了无条件和有条件异常检测的效果。

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英文摘要

Variational autoencoders (VAE) encode data into lower-dimensional latent vectors before decoding those vectors back to data. Once trained, one can hope to detect out-of-distribution (abnormal) latent vectors, but several issues arise when the latent space is high dimensional. This includes an exponential growth of the hypervolume with the dimension, which severely affects the generative capacity of the VAE. In this paper, we draw insights from high dimensional statistics: in these regimes, the latent vectors of a standard VAE are distributed on the `equators' of a hypersphere, challenging the detection of anomalies. We propose to formulate the latent variables of a VAE using hyperspherical coordinates, which allows compressing the latent vectors towards a given direction on the hypersphere, thereby allowing for a more expressive approximate posterior. We show that this improves both the fully unconditional-OOD and conditional-OOD anomaly detection ability of the VAE, achieving the best performance on the datasets we considered, outperforming existing methods. For the unconditional-OOD and conditional-OOD modalities, respectively, these are: i) detecting unusual landscape from the Mars Rover camera and unusual Galaxies from ground based imagery (complex, real world datasets); ii) standard benchmarks like Cifar10 and subsets of ImageNet as the in-distribution (ID) class.

2601.15065 2026-05-12 cs.CV

Enhancing Few-Shot Out-of-Distribution Detection via the Refinement of Foreground and Background

Tianyu Li, Zongqian Wu, Songyue Cai, Ping Hu, Xiaofeng Zhu

AI总结 该论文针对少样本分布外检测(Few-Shot OOD Detection)中前景-背景分解方法的不足,提出了一种新的即插即用框架。该方法通过自适应背景抑制和可混淆前景修正两个核心模块,分别优化背景区域的分类熵权重和修正与其它类别相似的前景区域,从而提升检测性能。实验表明,该框架有效提升了现有方法在少样本场景下的分布外检测能力。

Comments arXiv preprint arXiv:2601.15065 (2026)

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英文摘要

CLIP-based foreground-background (FG-BG) decomposition methods have demonstrated remarkable effectiveness in improving few-shot out-of-distribution (OOD) detection performance. However, existing approaches still suffer from several limitations. For background regions obtained from decomposition, existing methods adopt a uniform suppression strategy for all patches, overlooking the varying contributions of different patches to the prediction. For foreground regions, existing methods fail to adequately consider that some local patches may exhibit appearance or semantic similarity to other classes, which may mislead the training process. To address these issues, we propose a new plug-and-play framework. This framework consists of three core components: (1) a Foreground-Background Decomposition module, which follows previous FG-BG methods to separate an image into foreground and background regions; (2) an Adaptive Background Suppression module, which adaptively weights patch classification entropy; and (3) a Confusable Foreground Rectification module, which identifies and rectifies confusable foreground patches. Extensive experimental results demonstrate that the proposed plug-and-play framework significantly improves the performance of existing FG-BG decomposition methods. Code is available at: https://github.com/lounwb/FoBoR.

2601.11258 2026-05-12 cs.LG cs.AI cs.CL

Knowledge is Not Enough: Injecting RL Skills for Continual Adaptation

Pingzhi Tang, Yiding Wang, Muhan Zhang

AI总结 大型语言模型(LLMs)面临“知识截止”问题,即其固定参数难以直接吸收新信息。尽管监督微调(SFT)常用于更新模型知识,但往往无法有效提升模型对新知识的运用能力。本文提出参数技能迁移(PaST)框架,通过从源领域提取领域无关的技能向量,并在轻量级SFT后将其线性注入目标模型,实现高效且有效的知识适应。实验表明,PaST在问答和工具使用等任务中均取得显著提升,展示了其良好的可扩展性和跨领域迁移能力。

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英文摘要

Large Language Models (LLMs) face the "knowledge cutoff" challenge, where their frozen parametric memory prevents direct internalization of new information. While Supervised Fine-Tuning (SFT) is commonly used to update model knowledge, it often updates factual content without reliably improving the model's ability to use the newly incorporated information for question answering or decision-making. Reinforcement Learning (RL) is essential for acquiring reasoning skills; however, its high computational cost makes it impractical for efficient online adaptation. We empirically observe that the parameter updates induced by SFT and RL are nearly orthogonal. Based on this observation, we propose Parametric Skill Transfer (PaST), a framework that supports modular skill transfer for efficient and effective knowledge adaptation. By extracting a domain-agnostic Skill Vector from a source domain, we can linearly inject knowledge manipulation skills into a target model after it has undergone lightweight SFT on new data. Experiments on knowledge-incorporation QA (SQuAD, LooGLE) and agentic tool-use benchmarks (ToolBench) demonstrate the effectiveness of our method. On SQuAD, PaST outperforms the state-of-the-art self-editing SFT baseline by up to 9.9 points. PaST further scales to long-context QA on LooGLE with an 8.0-point absolute accuracy gain, and improves zero-shot ToolBench success rates by +10.3 points on average with consistent gains across tool categories, indicating strong scalability and cross-domain transferability of the Skill Vector.

2601.02954 2026-05-12 cs.SD cs.AI

The World is Not Mono: Enabling Spatial Understanding in Large Audio-Language Models

Yuhuan You, Lai Wei, Xihong Wu, Tianshu Qu

AI总结 这篇论文提出了一个名为“The World is Not Mono (TWNM)”的框架,旨在增强大型音频-语言模型对声音事件空间位置的理解能力。研究通过引入基于物理原理的First-Order Ambisonics(FOA)模拟,结合多通道音频学习空间感知表示,并融合语义特征,从而实现对声音场景的多层次分析。该方法在构建的基准测试中表现出色,显著提升了模型在空间定位、场景推理等任务上的性能。

Comments 25 pages, 4 figures

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英文摘要

Large audio-language models have made rapid progress in recognizing what is present in an audio clip, but spatial audio-language understanding still lacks a clear task interface. A model must also decide where sound events occur, which semantic and spatial attributes belong to the same auditory object, how multiple objects are arranged, and whether a scene-level answer is physically plausible. We formalize this capability as audio scene analysis (ASA), a three-level problem spanning atomic perception, relational integration, and cognitive reasoning. We propose The World is Not Mono (TWNM), a framework that equips audio-language models with explicit spatial evidence. TWNM uses physically grounded First-Order Ambisonics (FOA) simulation for controllable supervision, learns slot-regularized spatial representations from multichannel audio, fuses them with semantic audio features, and trains with a progressive curriculum ending in preference optimization over metadata-derived answers and auxiliary format/evidence rewards. To operationalize ASA, we build a controlled benchmark from scene metadata, covering localization, attribute binding, spatial comparison, scene abduction, and counterfactual reasoning. On this benchmark, TWNM achieves 70.8% overall accuracy, 66.4% on spatial-family tasks, and 79.76% on mixed L3 scene-level multiple-choice QA. We also audit monaural and binaural reference systems as diagnostic references with explicit audit labels, since they differ in spatial input, training interface, and output format. The supported claim is that a clearly defined ASA hierarchy, FOA-conditioned spatial representations, and metadata-grounded training enable controlled, auditable spatial audio-language reasoning, with STARSS23 providing a limited real-recording diagnostic.

2601.02950 2026-05-12 cs.AI

Batch-of-Thought: Cross-Instance Learning for Enhanced LLM Reasoning

Xuan Yang, Furong Jia, Roy Xie, Xiong Xi, Hengwei Bian, Jian Li, Monica Agrawal

AI总结 当前大型语言模型的推理系统通常独立处理每个查询,忽略了不同实例之间的共享推理模式和一致性约束等有价值的信息。本文提出了一种无需训练的Batch-of-Thought(BoT)方法,通过联合处理相关查询实现跨实例学习,从而提升推理质量并降低计算成本。实验表明,BoT在多个模型和基准测试中显著提高了准确性和置信度校准,同时减少了高达61%的推理成本。

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英文摘要

Current Large Language Model reasoning systems process queries independently, discarding valuable cross-instance signals such as shared reasoning patterns and consistency constraints. We introduce Batch-of-Thought (BoT), a training-free method that processes related queries jointly to enable cross-instance learning. By performing comparative analysis across batches, BoT identifies high-quality reasoning templates, detects errors through consistency checks, and amortizes computational costs. We instantiate BoT within a multi-agent reflection architecture (BoT-R), where a Reflector performs joint evaluation to unlock mutual information gain unavailable in isolated processing. Experiments across three model families and six benchmarks demonstrate that BoT-R consistently improves accuracy and confidence calibration while reducing inference costs by up to 61%. Our theoretical and experimental analysis reveals when and why batch-aware reasoning benefits LLM systems. Our code is available at https://github.com/xuanyang19/BoT

2512.24863 2026-05-12 cs.CL cs.AI cs.CY

Big AI is accelerating the metacrisis: What can we do?

Steven Bird

AI总结 当前世界正面临生态、意义和语言危机的叠加,即“元危机”,而大型人工智能(Big AI)正在加剧这一趋势。研究指出,尽管大型语言模型(LLM)的开发初衷具有公共利益导向,但其工程化应用却加剧了财富和权力的不平等,并对地球生态和人类生存构成威胁。文章呼吁自然语言处理领域从业者共同探索替代方案,推动以人类福祉和地球生命为中心的可持续发展路径。

Comments 12 pages, 2 figures, to appear in Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026), San Diego, July 2026

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英文摘要

The world is in the grip of ecological, meaning, and language crises that are converging into a metacrisis. Big AI is accelerating them all. LLM engineering sits at the core. Despite the public good motives of language engineers and the promise of LLMs, this work is being leveraged to create unprecedented wealth and power for a handful of individuals and corporations while causing existential harm to life on earth. As a profession, we urgently need to come together to explore alternatives and to design a life-affirming future for our field of natural language processing that is centered on human flourishing on a living planet.

2512.19219 2026-05-12 cs.CV cs.AI

Selective LoRA for Visual Tokens and Attention Heads

Tiange Luo, Lajanugen Logeswaran, Jaekyeom Kim, Justin Johnson, Honglak Lee

AI总结 本文提出了一种面向视觉任务的参数高效微调方法Image-LoRA,针对视觉语言模型(VLM)输入的异构性,将LoRA的更新限制在视觉token和部分注意力头的值路径上,从而减少可训练参数和计算量。该方法在视觉定位任务中表现优异,尤其在视觉token占比高的情况下,与标准LoRA相比具有更优的性能与效率平衡,并在多个任务上验证了其通用性和文本处理的稳定性。

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英文摘要

Low-rank adaptation (LoRA) is widely used for parameter-efficient fine-tuning, but its standard all-token, all-head design ignores the heterogeneous structure of vision language model (VLM) inputs. We introduce \emph{Image-LoRA}, a vision-oriented PEFT recipe that views LoRA as a token-level residual update and applies this update only to visual tokens. Image-LoRA further restricts adaptation to the value path of a compact subset of attention heads, selected using a one-pass influence estimate from a rank-1 visual-token-only probe. This token-, head-, and value-selective design reduces trainable parameters and adapter-only training FLOPs while leaving the pure-text forward pass of the frozen backbone unchanged when no visual tokens are present. Across visual localization benchmarks with controlled text:image token ratios, Image-LoRA matches or closely approaches standard LoRA, while showing especially favorable trade-offs in image-token-heavy regimes. We further validate its generality on TextVQA and VideoQA, verify pure-text preservation on GSM8K, and show on ViLP that a stronger information bottleneck can yield gains over standard LoRA.

2512.18928 2026-05-12 cs.LG

The Ensemble Schr{ö}dinger Bridge filter for Nonlinear Data Assimilation

Hui Sun

AI总结 本文提出了一种新的非线性最优滤波方法,称为集合薛定谔桥非线性滤波器。该方法结合了标准的预测步骤与基于扩散生成模型的分析步骤,实现了完整的滤波更新过程,无需引入结构模型误差,且无需训练、无需求导、高度并行化。数值实验表明,该算法在高度非线性动力系统和观测过程下表现出色,包括高达40维以上的混沌系统,并在多种非线性程度的测试中优于经典的集合卡尔曼滤波和粒子滤波方法。

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英文摘要

This work introduces a novel nonlinear optimal filtering method, termed the Ensemble Schr{ö}dinger Bridge nonlinear filter. The proposed filter combines the standard prediction step with a diffusion-generative-modeling-based analysis step, thereby completing one full filtering update. The resulting approach introduces no structural model error, and is derivative-free, training-free, and highly parallelizable. Numerical experiments demonstrate that the proposed algorithm performs effectively for highly nonlinear dynamics and nonlinear observation processes, including chaotic systems with dimension up to 40 and beyond. The results also show that the method outperforms classical approaches such as the ensemble Kalman filter and particle filter across a range of tests with varying degrees of nonlinearity. Future work will focus on extending the proposed method to practical meteorological applications and developing a rigorous convergence theory.

2512.18880 2026-05-12 cs.CL cs.AI cs.CY

Can LLMs Estimate Student Struggles? Human-AI Difficulty Alignment with Proficiency Simulation for Item Difficulty Prediction

Ming Li, Han Chen, Yunze Xiao, Jian Chen, Hong Jiao, Tianyi Zhou

AI总结 本文探讨了大型语言模型(LLMs)是否能够准确估计学生在学习任务中的困难程度,这是教育评估中的关键问题。研究通过大规模实证分析发现,尽管LLMs在解决问题方面表现出色,但它们在模拟学生认知困难方面存在系统性偏差,且模型规模的扩大并不一定能提升难度估计的准确性。研究还指出,模型在预测自身局限性方面存在严重不足,表明当前模型的通用解题能力并不等同于对人类认知挑战的理解。

Comments ACL2026, camera-ready

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英文摘要

Accurate estimation of item (question or task) difficulty is critical for educational assessment but suffers from the cold start problem. While Large Language Models demonstrate superhuman problem-solving capabilities, it remains an open question whether they can perceive the cognitive struggles of human learners. In this work, we present a large-scale empirical analysis of Human-AI Difficulty Alignment for over 20 models across diverse domains such as medical knowledge and mathematical reasoning. Our findings reveal a systematic misalignment where scaling up model size is not reliably helpful; instead of aligning with humans, models converge toward a shared machine consensus. We observe that high performance often impedes accurate difficulty estimation, as models struggle to simulate the capability limitations of students even when being explicitly prompted to adopt specific proficiency levels. Furthermore, we identify a critical lack of introspection, as models fail to predict their own limitations. These results suggest that general problem-solving capability does not imply an understanding of human cognitive struggles, highlighting the challenge of using current models for automated difficulty prediction.