NeurIPS 2026 论文列表

Conference on Neural Information Processing Systems

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6,437篇论文

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Amortized Guidance for Image Inpainting with Pretrained Diffusion Models

Yilie Huang, XUNYU ZHOU

展开摘要

We study image inpainting with generative diffusion models. Existing methods typically either train dedicated task-specific models, or adapt a pretrained diffusion model separately for each masked image at deployment. We introduce a middle-ground model, termed Amortized Inpainting with Diffusion (AID), which keeps a pretrained diffusion backbone fixed, trains a small reusable guidance module offline, and then reuses it across masked images without per-instance optimization. We formulate it as a deterministic guidance problem with a supervised terminal objective. To make this problem learnable in high dimensions, we derive an auxiliary Gaussian formulation and prove that solving this randomized problem recovers the optimal deterministic guidance field. This bridge yields a principled continuous-time actor--critic algorithm for learning the guidance module in a fully data-driven manner. Empirically, on AFHQv2 and FFHQ under the pixel EDM pipeline and on ImageNet under the latent EDM2 pipeline, AID consistently improves the quality--speed trade-off over strong fixed-backbone and amortized inpainting baselines across multiple mask types, while adding less than one percent trainable overhead.

Poster
AmbiguousWorld: Benchmarking and Resolving Ambiguous Instructions in Video World Models

Bo Wang, Sen Cui, Jin Li, Ming Hei Huang, Zhikang Chen, Min Zhang, Guocai Yao, Changshui Zhang

展开摘要

Translating high-level, under-specified human commands into coherent video is fundamentally challenging. Current video generation models lack explicit reasoning capabilities and typically fail to understand ambiguous instructions, frequently resulting in physically inconsistent and causally disjointed generation. To address this, we introduce AmbiguousWorld, a novel inference-time reasoning framework that transforms video generation into a multi-modal Tree of Thoughts. We employ a Vision-Language Model as both a semantic planner to dynamically decompose fuzzy instructions into actionable subgoals, and as a closed-loop critic to prune invalid trajectories by evaluating speculative paths across multiple physical and functional dimensions. To systematically assess this, we annotate the first embodied video generation benchmark targeting ambiguous instructions based on the DROID dataset, and design a multi-dimensional VLM evaluation framework. Empirical results on state-of-the-art baselines demonstrate that our framework yields substantial improvements, boosting absolute Task Success by up to 29.0\% and the overall generative consistency weighted score by 24.2 points. Furthermore, we validate the effectiveness of our VLM evaluation framework through rigorous comparison with human assessment.

Poster
AmbientFM: A Foundation Model for Ambient Sensing

Guozhen Zhu, Yuqian Hu, Sakila S Jayaweera, Wei-Hsiang Wang, Weihang Gao, Jiaxuan Zhang, Beibei Wang, Chenshu Wu, K. Liu

展开摘要

Ambient intelligence seeks to continuously understand human presence, activity, and physiology in physical spaces, enabling smart environments, health monitoring, and human-computer interaction. WiFi infrastructure offers a ubiquitous, always-on, and privacy-preserving sensing substrate across billions of IoT devices. Yet ambient sensing with WiFi remains largely fragmented, with most systems relying on task-specific models, labeled data collection, and customized training pipelines. We present AmbientFM, the first foundation model for ambient sensing through ubiquitous WiFi signals. AmbientFM is pre-trained on 9.2 million unlabeled Channel State Information (CSI) samples collected over 439 days from 20 commercial device types deployed in real-world environments. It learns transferable wireless representations through contrastive learning, masked reconstruction, and physics-informed objectives tailored to wireless signals. With lightweight adaptation, a single backbone transfers to 9 downstream tasks, achieving above 0.90 AUROC on all classification benchmarks and supporting dense spatial reconstruction. AmbientFM reduces the need for labeled data and task-specific design, enabling scalable ambient intelligence on existing wireless infrastructure.

Poster
AlphaQ: Calibration-Free Bit Allocation for Mixture-of-Experts Quantization

Wanqi Yang, Yuexiao Ma, Alexander Conzelmann, Xiawu Zheng, Michael Mahoney, T. Konstantin Rusch, Shiwei Liu

展开摘要

Mixture-of-Experts (MoE) architectures scale model capacity through sparse expert activation, but their deployment remains memory-bound because all expert weights must reside in memory. Mixed-precision quantization can substantially reduce this footprint by assigning different bit-widths to different experts. Existing approaches, however, typically rely on calibration data to estimate expert importance and determine bit allocation. For frontier MoE LLMs, the original training data, and hence the true training distribution, is proprietary and inaccessible. As a result, calibration sets are inevitably imperfect surrogates, which can misestimate expert utilization and lead to suboptimal bit allocation. Motivated by the substantial cross-expert quality variability observed in modern MoE models, we propose AlphaQ, a calibration-free bit-allocation method for MoE quantization. AlphaQ draws on Heavy-Tailed Self-Regularization (HT-SR) theory and follows a simple principle: experts with more heavy-tailed weight spectra are typically better trained and should receive higher bit-widths, while experts with weaker heavy-tailed structure can be quantized more aggressively. AlphaQ operationalizes this principle by measuring expert-wise spectral heavy-tailedness and solving a budget-constrained optimization problem that minimizes total quantization error under a global bit-budget constraint. Across several MoE models, AlphaQ consistently outperforms calibration-based baselines under matched bit budgets. Notably, on Qwen1.5-MoE, AlphaQ achieves near full-precision accuracy with an average expert precision of only 3.5 bits, while delivering more than 4$\times$ memory compression.

Poster
AlphaPareto: Formulaic Alpha Discovery with LLM-Guided Multi-Objective Reinforcement Learning

Yingbo Zhao, Zeyu Yang, Zhoufan Zhu

展开摘要

Formulaic alpha discovery is a core challenge in quantitative trading, as identifying alphas that work well together remains difficult. Recent reinforcement learning (RL) methods formulate this task as a Markov decision process (MDP), but two important issues remain unresolved. First, as the alpha pool evolves, the reward function changes accordingly, making the MDP inherently non-stationary. Second, most existing methods optimize a single objective, typically predictive power, while ignoring other important properties of a high-quality alpha pool. Motivated by these challenges, we propose AlphaPareto, an RL method for formulaic alpha discovery. To address non-stationarity, AlphaPareto augments the state to include both the alpha under construction and the current alpha pool, and applies a large language model (LLM) to encode the pool. This design allows the agent to adapt to the evolving search environment. To overcome the limitation of single-objective reward design, AlphaPareto replaces the scalar reward with a multi-objective vector-valued reward that simultaneously captures predictive power, temporal stability, perturbation robustness, and diversity, and optimizes these objectives through a Pareto-regularized learning procedure. Empirical applications to real-world datasets show that our AlphaPareto method outperforms its competitors.

Poster
AlphaPROBE: Alpha Mining via principled retriveval and on-graph biased evolution

Taian Guo, Haiyang SHEN, Junyu Luo, Binqi Chen, Hongjun Ding, Jinsheng Huang, Luchen Liu, Yun Ma, Ming Zhang

展开摘要

Extracting signals through alpha factor mining is a fundamental challenge in quantitative finance. Existing automated methods primarily follow two paradigms: Decoupled Factor Generation, which treats factor discovery as isolated events, and Iterative Factor Evolution, which focuses on local parent-child refinements. However, both paradigms lack a global structural view, often treating factor pools as unstructured collections or isolated single-lineage paths, which leads to redundant search and inefficient allocation of optimization effort. To address these limitations, we introduce AlphaPROBE, (**Alpha** Mining via **P**rincipled **R**etrieval and **O**n-graph **B**iased **E**volution), a framework that reframes alpha mining as the strategic navigation of a Directed Acyclic Graph (DAG). By modeling factors as nodes and evolutionary links as edges, AlphaPROBE treats the factor pool as a dynamic, interconnected ecosystem. The framework consists of two core components: a Bayesian Factor Retriever that identifies high-potential seeds by balancing exploitation and exploration through a posterior probability model, and a DAG-aware Factor Generator that leverages the full ancestral trace of factors to produce context-aware, non-redundant optimizations. Extensive experiments on major Chinese and US stock market datasets against 8 competitive baselines demonstrate that AlphaPROBE significantly gains enhanced performance in predictive accuracy, return stability and training efficiency. Our results confirm that leveraging global evolutionary topology is essential for efficient and robust automated alpha discovery. We have open-sourced our implementation at https://anonymous.4open.science/r/AlphaPROBE-A103.

Poster
Allocentric Perceiver: Disentangling Allocentric Reasoning from Egocentric Visual Priors via Frame Instantiation

Hengyi Wang, RuiQiang Zhang, Chang Liu, Guanjie Wang, Zehua Ma, Han Fang, Weiming Zhang

展开摘要

With the rising need for spatially grounded tasks such as Vision-Language Navigation/Action, allocentric perception capabilities in Vision-Language Models (VLMs) are receiving growing focus. However, VLMs remain brittle on allocentric spatial queries that require explicit perspective shifts, where the answer depends on reasoning in a target-centric frame rather than the observed camera view. Thus, we introduce $\textbf{Allocentric Perceiver}$, a training-free strategy that recovers metric 3D states from one or more images with off-the-shelf geometric experts, and then instantiates a query-conditioned allocentric reference frame aligned with the instruction’s semantic intent. By deterministically transforming reconstructed geometry into the target frame and prompting the backbone VLM with structured, geometry-grounded representations, Allocentric Perceiver offloads mental rotation from implicit reasoning to explicit computation. We evaluate Allocentric Perceiver across multiple backbone families on spatial reasoning benchmarks, observing consistent and substantial gains ($\sim$\textbf{10\%}) on allocentric tasks while maintaining strong egocentric performance, and surpassing both spatial‑perception-finetuned models and state‑of‑the‑art open‑source and proprietary models.

Poster
AlloGen: Conformation-Selective Binder Design with Differential State Scoring

Hanqun CAO, Aastha Pal, Sumi Kimura, Yesol Kim, Jingjie Zhang, Pheng-Ann Heng, Pranam Chatterjee

展开摘要

Protein binder design has largely optimized for affinity alone, leaving conformational selectivity unaddressed: for allosteric targets such as kinases, nuclear receptors, and GPCRs, a binder that engages both active and inactive states provides no functional specificity regardless of how tightly it binds. We introduce **AlloGen**, a modular framework that decouples backbone generation from a learned state-selectivity scorer $Q_\theta$, an SE(3)-invariant interface graph transformer trained via a two-phase curriculum that first grounds interface geometry before imposing conformational discrimination. Because $Q_\theta$ is fully differentiable and generator-agnostic, it integrates with any backbone generator as a passive reranker or an active gradient-based guide without retraining. Trained on 65 targets spanning 15 protein families, $Q_\theta$ generalizes to held-out out-of-distribution targets where energy-based baselines fail entirely, and all 15 evaluated generator--guidance combinations achieve positive conformational selectivity averaged over the held-out targets, with the best reaching $\bar{S}=+0.677$. Our anonymous code repository can be found at https://anonymous.4open.science/r/AlloGen_NeurIPS-04CB.

Poster
All-Addition Spiking Diffusion Models with Attention Enhancement

Yuhan Zhang, Yuanpei Chen, Zhou Jie, Weihang Peng, Xiaode Liu, Yinglei Wang, Yufei Guo

展开摘要

Diffusion models have achieved state-of-the-art (SoTA) performance in generative tasks through their iterative denoising mechanism, yet they remain computationally intensive and energy-prohibitive. Spiking Neural Networks (SNNs) represent a promising energy-efficient alternative to traditional Artificial Neural Networks (ANNs). Their binary spike encoding enables the conversion of multiplication operations into addition operations, which is a key attribute for reducing energy consumption. Integrating the strong generative capabilities of diffusion models with the energy efficiency of SNNs thus forms a highly promising research direction. In adherence to the design goal of all-additive computation, this paper proposes a novel spiking diffusion model with attention enhancement. Specifically, we adopt non-negative ternary spiking neurons (NNTSN) to construct the U-Net backbone, which helps mitigate information loss during feature processing. To align NNTSN with the requirement of using only additive operations, we further design two core components: a membrane potential attention mechanism and an all-additive shortcut module. Leveraging a reparameterization technique, the proposed diffusion model is developed to retain only additive operations during inference, ensuring strict compliance with energy-saving design principles. Extensive experiments on relevant benchmarks demonstrate that our method achieves SoTA performance in generative tasks. It also substantially outperforms other SNN-based generative models while using fewer time steps, which validates both its effectiveness and efficiency.

Spotlight
All Roads Lead to Rome: Flow-driven Multi-Anchor Exploration for Open-Environment Active 3D Mapping

Yang Li, Aming WU, Zihao Zhang, Ziju Han, Sijia Zhang, Yahong Han

展开摘要

To advance the development of embodied intelligence, Open-Environment Active 3D Mapping has attracted increasing attention, aiming to perform a long-horizon and shortest trajectory exploration for reconstructing unseen scenarios. Since only limited information about unseen environments is available, methods built on the closed-set assumption, i.e., assuming that the test environments are similar to those seen during training, cannot generalize satisfactorily. In existing active mapping methods, long-horizon exploration is often guided by predicting a coarse long-range goal and then converting it into an executable path. However, this stage is usually formulated as single-point prediction. Under partial observability, the same local observation may correspond to multiple plausible exploration directions, making such deterministic prediction prone to brittle decisions and degraded performance in unseen scenarios. Our experiments further verify that this is a key factor underlying their weak generalization. To address this issue, we reformulate long-horizon target prediction as conditional multimodal anchor generation using Conditional Flow Matching. Instead of predicting a single goal, our method learns a conditional distribution over coarse exploration anchors from the current mapping state. These anchors are first converted into executable candidate paths through obstacle-aware planning. We then apply exploration-mode clustering to compress geometrically similar trajectories and reduce candidate redundancy. Finally, a hierarchical selection module selects the most promising mode and reranks paths within it to produce the final executable trajectory. Experiments show that our method improves generalization and reconstruction efficiency in open environments.

Spotlight
Alignment Is Not Enough for Safe Medical LLM Evaluation

Zhiwen You, Yikun Han, Jana Diesner, Yue Guo

展开摘要

LLMs-as-judges (LLJs) are increasingly used to reduce the cost of expert review in medical evaluation. However, high alignment with clinicians does not by itself establish validity or safety. This position paper argues that current reporting practices for medical LLJs are insufficient: LLJ-clinician alignment should not be reported as standalone evidence that a judge is reliable, clinically grounded, or safe for downstream use. We identify four risks: unstable evaluations across prompts, runs, and judge models; opaque scores that hide clinically meaningful errors; weak validity under clinical uncertainty and limited clinician agreement; and downstream safety or data contamination risks when flawed scores influence model selection or synthetic data filtering. By re-examining LLJ evaluation setups used in prior medical studies, we show that judges treated as practical evaluators in the literature can still reject clinically equivalent diagnoses, overrate incomplete or unsafe answers, reward unsupported clinical notes, and penalize appropriate treatment plans. We propose a protocol for medical LLJ evaluation that requires task-specific codebooks, expert-annotated validation sets, codebook-derived prompts, robustness testing, clinical error analysis, uncertainty reporting, and transparent disclosure before LLJ scores are used for medical benchmarking or decision support.

Poster
Alignment Imprint: Zero-Shot AI-Generated Text Detection via Provable Preference Discrepancy

Junxi Wu, Kailin Huang, Dongjian Hu, Bin CHEN, Hao Wu, Shu-Tao Xia, Changliang Zou

展开摘要

Detecting AI-generated text is an important but challenging problem. Existing likelihood-based detection methods are often sensitive to content complexity and may exhibit unstable performance. In this paper, our key insight is that modern Large Language Models (LLMs) undergo alignment (including fine-tuning and preference tuning), leaving a measurable distributional imprint. We theoretically derive this imprint by abstracting the alignment process as a sequence of constrained optimization steps, showing that the log-likelihood ratio can naturally decompose into implicit instructional biases and preference rewards. We refer to this quantity as the Alignment Imprint. Furthermore, to mitigate the instability in high-entropy regions, we introduce Log-likelihood Alignment Preference Discrepancy (LAPD), a standardized information-weighted statistic based on alignment imprint. We provide statistical guarantee that alignment-based statistics dominate Fast-DetectGPT in performance. We also theoretically show that LAPD strictly improves the unweighted alignment scores when the aligned and base models are close in distribution. Extensive experiments show that LAPD achieves an improvement 45.82% relative to the strongest existing baselines, yielding large and consistent gains across all settings

Poster
Alignment Dynamics in LLM Fine-Tuning

Yuhan Huang, Huanran Chen, Yinpeng Dong

展开摘要

Although Large Language Models (LLMs) achieve strong alignment through supervised fine-tuning and reinforcement learning from human feedback, the alignment is often fragile under subsequent fine-tuning. Existing explanations either attribute alignment fragility to gradient geometry or characterize it as a distributional shift in model outputs, yet few provide a unified account that bridges parameter-space learning dynamics with function-space alignment behavior during fine-tuning. In this work, we introduce a tractable alignment score and derive its closed-form update during fine-tuning, yielding a unified framework for alignment dynamics. Our analysis decomposes alignment updates into two competing components: a Rebound Force, governed jointly by the current alignment state and the narrowness of model distribution, and a Driving Force, determined by how the training distribution aligns with outcome-conditioned posteriors over aligned and non-aligned completions. This decomposition explains why prior alignment can be reversed by later fine-tuning and why narrower posterior structure strengthens such reversal. Moreover, our framework predicts a Rehearsal Priming Effect: prior alignment leaves a latent posterior imprint that amplifies the effective Driving Force upon re-exposure, leading to faster re-alignment. We validate these predictions across safety alignment, emergent misalignment, and sentiment settings, demonstrating consistent alignment reversal and accelerated re-alignment under re-exposure. In addition, controlled experiments in safety alignment confirm the predicted dependence of rebound strength on posterior narrowness. Together, these results provide a unified dynamical perspective on how alignment is disrupted and reactivated during LLM fine-tuning.

Poster
Alignment Collapse Under KV Cache Quantization: Diagnosis and Mitigation

Bruce C Xu, Adarsh Kumarappan, Mu Zhou

展开摘要

Key--value (KV) cache quantization is widely used to reduce Large Language Model (LLM) inference memory, yet existing evaluations solely focus on measuring perplexity and accuracy without assessing the safety impact. In this study, we explore alignment preservation under KV cache quantization. Across eleven instruction-tuned models (3.8B--72B) and five benchmarks (1,894 prompts), we find that low-bit quantization can silently destroy safety alignment (Mistral-7B loses 15.2\% of its refusals at only $1.03\times$ perplexity, and no universal safe bit-width exists), with sharp model-specific phase transitions invisible to standard metrics. We identify that the root cause is geometric: safety features occupy a low-dimensional activation subspace $10^2$-$10^3\times$ more vulnerable to quantization noise than the full representation space perplexity averages over. Inspired by this observation, we propose **Per-Channel Reduction** (PCR), a diagnostic that classifies each model into one of three mechanistic failure modes: (i) *outlier-crushes-safety*, where safety lives in non-outlier channels collaterally damaged by outlier-driven scale factors; (ii) *outlier-as-safety*, where safety overlaps outlier channels and finer granularity cannot rescue it; (iii) *multi-layer dilution*, where safety is distributed across many layers and per-layer fixes fail. PCR predicts the correct mitigation direction on all nine primary models and one held-out model from an independent family (20 calibration prompts). PCR generalizes across unseen prompts, models, and production quantizers (KIVI: up to 97.2\% recovery), succeeding where attention-based allocation methods fail. The resulting training-free protocol (${\sim}35$ GPU-minutes) recovers up to 97\% of lost alignment at minimal memory overhead, addressing vulnerabilities confirmed in production vLLM serving with FP8 KV cache on NVIDIA GPUs.

Poster
Aligning MLLMs with the Latent Structure of Human Cognition via Behavior-Derived Semantic Dimensions

Ning E, Changde Du, Yizhuo Lu, Huiguang He

展开摘要

Multimodal Large Language Models (MLLMs) have achieved impressive performance across a wide range of reasoning tasks, yet it remains unclear whether their internal representations and decision criteria align with the latent structure of human cognition. In this work, we propose a novel framework to align MLLMs with the multidimensional mental representations underlying human similarity judgements. We build on a previously established behavior-derived semantic embedding space, in which objects are represented along 66 interpretable dimensions derived from 4.70 million human Odd-One-Out (O1O) judgements. For each triplet, we infer the most salient decision dimension and convert it into a dimension-grounded linguistic rationale. This enables MLLMs to learn both the final choice and a justification consistent with the inferred behavioral criterion. Experimental results demonstrate that our approach improves model consistency with human similarity judgements while retaining competitive performance on standard multimodal benchmarks. Furthermore, using searchlight Representational Similarity Analysis (RSA) on an independent fMRI Natural Scenes Dataset (NSD), we observe increased representational alignment between model and human. Ultimately, our findings point to a data-driven route for incorporating human cognitive structure into MLLMs alignment.

Poster
Aligning Language Model Benchmarks with Pairwise Preferences

Marco Gutierrez, Xinyi Leng, Hannah Chen, Jonathan Richard Schwarz, Ahmed Alaa, Tom Hartvigsen

展开摘要

Language model benchmarks are pervasive and computationally-efficient proxies for real-world downstream performance. However, many recent works find that benchmarks often fail to predict downstream utility. While some works have begun diagnosing sources of misalignment, there remain no ways to systematically update benchmarks to align their scores with downstream usage. Towards bridging this gap, we introduce and study \textit{benchmark alignment}, where we use information about downstream model performance to automatically update benchmarks, aiming to produce new static benchmarks that predict model pairwise rankings on downstream tasks. Our experiments involving 4576 language models and 6 benchmarks show that benchmark items can successfully be reweighted to predict downstream performance for unseen models, even generalizing across model scales in most cases. And while naive alignment unsurprisingly requires large numbers of models and benchmark questions, we find that proper use of downstream data can often also enable alignment, even using responses from as few as 20 models. Overall, our work takes a step towards efficiently aligning benchmark development with downstream tasks.

Poster
Aligning LLMs with Biomedical Knowledge using Balanced Fine-Tuning

Zhenchao Tang, Fang Wang, Haohuai He, Jiale Zhou, Tianxu Lv, Jun Zhu, Shou Z Chen, Minghao Yang, Yu Wang, Jiayang Wu, Yidong Song, Yaokun Li, Jiehui Huang, JUN ZHOU, Bing He, Jianhua Yao

展开摘要

Engineering LLMs to accelerate life sciences research requires a robust alignment with biomedical knowledge. We observe that biomedical text exhibits a fundamentally different uncertainty structure from general text: dense low-confidence runs encode epistemic knowledge gaps (dense causal chains, rare entities) rather than the sparse aleatoric stylistic variation typical of general text. Based on this discovery, we propose Balanced Fine-Tuning (BFT), a dual-scale post-training method that combines group-normalized token reweighting with sequence-level reallocation toward knowledge-dense samples exhibiting dense epistemic uncertainty. Across medical evaluation, biological reasoning, sparse-reward RL, and biological representation tasks, BFT provides more consistent gains than SFT and DFT under a shared training setup. When replacing the default closed-source backbones in GeneAgent (GPT-4o) and VCWorld (Gemini-2.5-Flash), the BFT-aligned 70B model delivers stronger performance across biological process reasoning and chemical perturbation prediction. Critically, all BFT variants further improve after subsequent GRPO with sparse rewards, while SFT and DFT degrade, suggesting that epistemic-aware post-training provides a more robust policy initialization. Beyond text generation, BFT-aligned LLMs produce more accurate and professional biomedical profile texts; after encoding these profiles with a text embedding model, the resulting representations support gene-level, cell-level, and perturbation-response tasks, suggesting that BFT-enhanced generation can facilitate biological representation and, in turn, broader biomedical downstream tasks.

Poster
Aligning LLMs Toward Multi-Turn Conversational Outcomes Using Iterative RLHF

Daniel Jiang, Ankur Samanta, Yukai Yang, Jalaj Bhandari, Remi Munos, Tyler Lu

展开摘要

Training large language models (LLMs) as multi-turn conversational agents remains a significant challenge, particularly in goal-oriented settings. The difficulty stems from sparse, long-horizon objectives and the discrepancy between response-level planning and token-level generation. In this paper, we present a formal reduction of the multi-turn RL problem into a \emph{sequence of single-turn RLHF-style problems}. This is achieved by setting a learned multi-turn Q-function as the reward model for the single-turn problem. We demonstrate and prove a key insight: solving this single-turn RLHF problem with standard token-level GRPO is equivalent to an approximate policy improvement step within the multi-turn problem. This insight naturally leads to \emph{Iterative GRPO}, a batch online approximate policy iteration algorithm that alternates between collecting a batch of data from the current policy, fitting Q-functions from these logged conversation trajectories, and improving the policy via single-turn RLHF. A major practical advantage is that Iterative GRPO directly leverages stable, off-the-shelf single-turn RLHF tools, making it straightforward to implement. In addition, the method occupies a middle ground between fully online and fully offline approaches, retaining the adaptability of online updates while gaining the stability benefits of offline training. Empirically, we demonstrate the effectiveness of Iterative GRPO on six multi-turn conversational environments.

Poster
Aligning Forest and Trees in Images & Long Captions for Visually Grounded Understanding

Byeongju Woo, Zilin Wang, Byeonghyun Pak, Sangwoo Mo, Stella X. Yu

展开摘要

Vision-language models such as CLIP often struggle to faithfully understand long, detail-rich captions, relying on dominant scene cues while overlooking fine-grained visual evidence. We propose a hierarchical vision-language learning principle for understanding scenes as part-to-whole compositions: before forming a whole-scene representation, a model should uncover what semantic parts appear where in the image. To this end, we propose CAFT (Cross-domain Alignment of Forests and Trees), a vision-language model that jointly learns local text-region alignment at intermediate representations and global image-text alignment at the final representation. Exploiting the organization of long captions, where local descriptions often correspond to scene parts, CAFT employs a fine-to-coarse image encoder and a part-whole text encoder to discover localized part semantics and progressively compose them into a global image-text representation. Trained on 30M image-text pairs, CAFT achieves state-of-the-art performance on six long-text retrieval benchmarks and exhibits strong scaling behavior. Experiments show that CAFT learns fine-grained representations that localize textual semantics in image regions without explicit region-level supervision.

Poster
Aligning Flow Map Policies with Optimal $Q$-Guidance

Christos Ziakas, Alessandra Russo, Joey Bose

展开摘要

Generative policies based on expressive model classes, such as diffusion and flow matching, are well-suited to complex control problems with highly multimodal action distributions. Their expressivity, however, comes at a significant inference cost: generating each action typically requires simulating many steps of the generative process, compounding latency across sequential decision-making rollouts. We introduce flow map policies, a novel class of generative policies designed for fast action generation by learning to take arbitrary-size jumps---including one-step jumps---across the generative dynamics of existing flow-based policies. We instantiate flow map policies for offline-to-online reinforcement learning and formulate online adaptation as a trust-region optimization problem that improves the critic's $Q$-value while remaining close to the offline policy. We theoretically derive Flow Map $Q$-Guidance Training (FMQ), a principled closed-form learning target that is optimal for adapting offline flow map policies under a critic-guided trust-region constraint. We further introduce $Q$-Guided Beam Search (QGBS), a stochastic flow-map sampler that combines renoising with beam search to enable iterative inference-time refinement. Across $12$ challenging robotic manipulation and locomotion tasks from OGBench and RoboMimic, FMQ achieves state-of-the-art performance in offline-to-online RL, outperforming the previous one-step policy MVP by a relative improvement of $21.3$% on the average success rate.

Poster