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Fan Yang

Publications and source records attributed to Fan Yang.

At least 19 recordsLinked to original sources

DeFM: Learning Foundation Representations from Depth for Robotics

Depth sensors are widely deployed across robotic platforms, and advances in fast, high-fidelity depth simulation have enabled robotic policies trained on depth observations to achieve robust sim-to-real transfer for a wide range of tasks. Despite this, representation learning for depth modality remains underexplored compared to RGB, where large-scale foundation models now define the state of the art. To address this gap, we present DeFM, a self-supervised foundation model trained entirely on depth images for robotic applications. Using a DINO-style self-distillation objective on a curated dataset of 60M depth images, DeFM learns geometric and semantic representations that generalize to diverse environments, tasks, and sensors. To retain metric awareness across multiple scales, we introduce a novel input normalization strategy. We further distill DeFM into compact models suitable for resource-constrained robotic systems. When evaluated on depth-based classification, segmentation, navigation, locomotion, and manipulation benchmarks, DeFM achieves state-of-the-art performance and demonstrates strong generalization from simulation to real-world environments. We release all our pretrained models, which can be adopted off-the-shelf for depth-based robotic learning without task-specific fine-tuning. Webpage: https://de-fm.github.io/

cs.RO↗

PDRVLA: A Vision-Language-Action Model with Physical Dynamics Representations

Vision--Language--Action (VLA) models generate robot actions from visual observations and language instructions, but their understanding of physical dynamics remains limited. Video world models can capture scene dynamics, yet generating future videos introduces high latency into the control loop. We introduce PDRVLA, whose lightweight Physical Dynamics Module extracts physical tokens from vision--language features to condition action generation without online video generation. The module learns through direct prediction of future RGB, depth, and optical-flow features, with auxiliary supervision through a frozen pretrained video world model. Training relies entirely on publicly available data, expanded through human-to-robot synthesis, subtask annotation, and embodied chain-of-thought (ECoT) annotation. Across four simulation benchmarks, PDRVLA achieves success rates of 99.3% on LIBERO, 89.9% on LIBERO-Plus, 93.6% on RoboTwin~2.0, and 81.5% on SimplerEnv. Ablations show improved future prediction with world-model supervision and evaluate how subtask conditioning, future object-pose supervision, and ECoT training affect action success.

cs.RO↗

Labference: Benchmarking the Reasoning-Action Connection in Robotic Laboratories

Realizing Embodied AI for Science requires robots to translate experimental goals into reliable physical procedures, reducing hazardous and repetitive human work while generating evidence for scientific discovery. Although language-based planning and learned manipulation provide complementary capabilities, their integration requires robots to adapt subsequent operations to actual execution outcomes. For example, an unsuccessful placement changes what must be done next, even when the experimental goal remains unchanged. Existing benchmarks assess planning, manipulation, and laboratory workflows through task completion and reasoning or execution metrics; however, aggregate performance leaves the connection between outcome-dependent choices and physical execution unresolved. To address this evaluation gap, we introduce Labference, a benchmark for evaluating how observed physical outcomes guide subsequent choices and how those choices translate into robotic laboratory actions. Its evaluation protocol is designed to test outcome-dependent behavioral adaptation through controlled evidence variations, while independently measuring operation selection, physical execution, and task completion. Matched Oracle-assisted continuations from shared checkpoints then assess which forms of support improve subsequent choices and task completion. Initial weighing evaluations reveal target-selection errors in the tested VLA policies despite successful object transfers, whereas GPT-driven control achieves correct selection but encounters execution failures and substantial computation costs. Together, these findings highlight the need to connect task-appropriate reasoning with reliable, timely action. By making this connection measurable and diagnosable, Labference supports targeted improvements toward autonomous experimentation for Embodied AI for Science.

cs.RO↗

MANTIS: Multi-Axis News Transformations for Instance-Wise Stress Testing and Worst-Case Training in Fake News Detection

Automated fake news detection is vital on social media, where fake news is easily rewritten to fool detectors. However, existing approaches typically rely on superficial writing cues or single-style text rewrites, resulting in poor robustness under diverse cosmetic modifications. We construct MANTIS-Bench, a multi-axis presentation-attack benchmark that pairs original news with rewritten views across writing style, emotional expression, and dissemination framing. We further propose MANTIS, an instance-adaptive adversarial framework enabling dynamic worst-case training tailored to each news article with zero inference-time overhead. This reframes fake news defense from heuristic format smoothing into targeted, fact-invariant credibility assessment. Experiments on MANTIS-Bench show that MANTIS reduces the Union Attack Success Rate (UASR) by 3.55 percentage points relative to SheepDog on GossipCop and consistently outperforms prior single-axis defenses on Macro-F1 while maintaining competitive clean accuracy, demonstrating the effectiveness of multi-axis and instance-adaptive worst-case training.

cs.CL↗

Collinear and Coplanar Altermagnetism in a Penrose Quasicrystal

We generalize the previous group-theory based classification of collinear magnetism in the quasicrystal (QC) to general magnetic states. Taking the Penrose lattice as an example, we find that all magnetic states belonging to 2D irreducible representations (IRRPs) of the $D_5$ point group, including collinear states and coplanar ones, correspond to altermagnetism (AM). Unlike conventional collinear AM wherein zero magnetism is protected by, e.g. rotation or mirror reflection, which globally flip the spin in the magnetic pattern, the zero magnetism in these 2D-IRRP states is instead protected by a special group-theory-orthogonality theorem that basis functions belonging to different IRRPs are always mutually orthogonal. Taking the single-orbital Penrose-Hubbard as an example, our linear-response theory based calculations show that the largest portion of the parameter space is occupied by these 2D-IRRP states, and our further Ginzburg-Landau theory based analysis reveals that the polarization directions of the two basis magnetic states in the 2D IRRPs can be either parallel or perpendicular, leading to collinear or coplanar magnetic states. The special group-theory-orthogonality compensation mechanism and the absence of the PT symmetry finally leads to AM states, which are to be verified by the spin split in the spin-dependent angle-resolved-photoemission-spectrum and the spin conductance. These intriguing collinear and coplanar AM can also emerge in other QCs.

cond-mat.str-el↗

Atmospheric Turbulence Profiling in the Lenghu Site Area Using MERRA-2 Data

The Lenghu site, in the Saishiteng Mountains of the northern Tibetan Plateau, has been identified as an excellent astronomical site from preliminary statistics of clear nights, sky background brightness, precipitable water vapour, total seeing and weather. Since 2022, several projects with apertures larger than 4 m have started construction or are being planned. Given the use of adaptive optics (AO) on these projects, in-depth measurements and analysis of the atmospheric turbulence above the site are required: the distribution and variation of the turbulence profiles provide a large-scale, climatological basis for site planning and for comparing candidate locations, complementing rather than replacing the on-site measurements needed for instrument design and operations. Predicting the atmospheric profiles of the site and its surroundings from satellite data, combined with on-site measurements, can help to optimise the site planning. This paper uses MERRA-2 reanalysis data to study the atmospheric profiles of the site and its environment, revealing the seasonal and long-term variations of the observing conditions. The reanalysis results are cross-checked against on-site ground-level instruments serving the same purpose. MERRA-2 overestimates the median free-atmosphere seeing by +0.22 arcsec (+50 %) while keeping the night-to-night correlation weak (r ~ 0.2), and underestimates the median total seeing by -0.24 arcsec (-27 %). It captures only ~22 % of the ground-layer turbulence and little of the observed seasonal amplitude of the free atmosphere. MERRA-2 is therefore suited to relative comparisons of spatial variability between locations and to climatological characterisation, not to quantitative AO applications or night-by-night assessment of profiles.

astro-ph.IM↗

AdaPolicy: Action-Driven Anticipatory Robot Policies via Next-Chunk Prediction

Endowing robot policies with anticipatory capabilities has proven effective in improving control performance. However, existing methods predominantly rely on explicit supervision derived from future observations, in either pixel or latent space, at the cost of additional architectural and computational complexity. Departing from explicit future supervision, we ask whether such foresight can be elicited directly from the action signal. To this end, we propose \textbf{AdaPolicy}, an \textbf{A}ction-\textbf{d}riven \textbf{a}nticipatory policy framework that shapes future-aware representations via cascaded next-chunk prediction. Specifically, an Online Action Head jointly produces the current action chunk and an evolved latent state. Building on this state, a cascaded Unrolled Action Head forecasts the next chunk, and the resulting loss flows back through the evolved state to instill implicit foresight into the online policy. Importantly, this training-only unroll requires no future-observation encoding, keeping AdaPolicy lightweight to train with zero inference-time overhead. Experiments on MetaWorld, RoboTwin 2.0, LIBERO, and real-world deployments demonstrate consistent gains across diverse settings, including up to $14$ percentage points on millimeter-precision tasks such as earphone assembly and shoelace threading. More details and visualizations are available at \href{https://teee111.github.io/AdaPolicy/}{https://teee111.github.io/AdaPolicy/}.

cs.RO↗

DetailAnywhere: Fashion Detail Generation via Cross-Modal Feature Alignment Distillation

Diffusion-based generative AI has achieved remarkable success in e-commerce applications such as virtual try-on, poster generation, and product background synthesis. However, when making online purchasing decisions for apparel, consumers also desire the freedom to examine specific detail regions of interest, such as collars, cuffs, and fabric textures, yet existing methods have not explicitly studied this setting. We therefore formalize a new, non-template task: Fashion Detail Generation with focus conditioning, and release FDBench, the first benchmark comprising 40K+ human-verified reference-detail pairs across 41 different categories. This task poses a unique semantic gap challenge: the model must bridge the correspondence between a focus marker on a product reference image and a photorealistic close-up view of the indicated region, while faithfully preserving the garment's identity, without any precise prompt. To bridge this gap, we propose Cross-modal Feature Alignment Distillation (CFAD), which leverages a fine-tuned DINOv3 teacher to align both branches of a Multimodal Diffusion Transformer in a shared semantic space via dual-branch distillation. To further improve consistency between generated details and reference images, we introduce a consistency reward model that jointly scores image pairs along three quality axes and optimizes generation via reinforcement learning. Experiments show that our model DetailAnywhere significantly outperforms all state-of-the-art opensource methods across all metrics and human evaluations.

cs.CV↗

RangeNav: Task-Aligned LiDAR Range-Image Pretraining for Robot Navigation

Autonomous mobile robots operating in dense crowds and cluttered sites require $360^\circ$ perception to react to surrounding hazards. While panoramic LiDAR offers full-surround coverage, learning representations within reinforcement learning (RL) is sample-inefficient under sparse rewards, and existing 3D pretrained point-cloud encoders are too memory-heavy for massively parallel RL simulation. We present RangeNav, a compact (183k parameters) LiDAR range-image encoder pretrained entirely on synthetic data. RangeNav uses anisotropic convolutions and circular padding to handle the extreme aspect ratio and azimuthal seam of range images. We pretrain the network using a navigation-aligned objective combining range reconstruction, semantic segmentation, and bird's-eye-view (BEV) prediction, then freeze it for policy learning. In simulation, adding semantic and BEV supervision increases success rates over a reconstruction-only baseline by an average of 32.03 and 23.73 percentage points (pp) in procedurally generated training and out-of-distribution realistic test environments, respectively. Zero-shot real-world deployments on a Unitree B2-W quadruped demonstrate robust navigation through dense crowds, low-light settings, and construction zones where limited-field-of-view depth policies struggle. Code and models will be open-sourced. Project website: https://rangenav.github.io/.

cs.RO↗

Néel Ordered Magnetic Phases in Bipartite Quasicrystals

Magnetism is a fundamental research area in which the recently proposed altermagnetism (AM) has become an emergent frontier. Very recently, the quasicrystal (QC) was proposed as a possible platform to realize AM. However, the existence of AM in QCs still lacks vigorous evidence. In this work, we adopt the sign-problem-free projector quantum Monte Carlo (PQMC) algorithm to investigate the magnetic phases in the half-filled Hubbard models in various 2D bipartite QCs, and always obtain Néel ordered states. While the Néel states in bipartite crystals are usually antiferromagnetism (AFM), we find it common that those in bipartite QCs can also be AM or ferrimagnetism (FIM). Based on symmetry analysis, combined with our comprehensive PQMC results, we propose a general criterion for determining the magnetism classes of the Néel states in a bipartite QC: According to whether the two sublattices are related by inversion, a non-inversion point-group operation such as mirror or rotation, or no operation about the unique symmetry center, the corresponding Néel state is AFM, AM or FIM / geometry-enforced AM (G-AM), respectively. The G-AM is a special type of $s$-wave AM caused by the unique QC structure formed through projection from high-dimensional crystals to lower dimensions, which is rare in crystals. For example, our results yield symmetry-protected AM for the two $D_4$-symmetric Thue-Morse QCs and G-AM for the $D_5$-symmetric Penrose QC at half-filling. Our results provide a solid foundation for experimental investigations and potential applications of different classes of magnetism in QCs.

cond-mat.str-el↗

From Partitioning to Provisioning: Co-Designing DNN Deployment and Infrastructure Capacity

Deep neural network (DNN) partitioning enables distributed inference by dividing model computation across interconnected devices. Existing approaches have largely focused on optimizing DNN deployment over infrastructure with fixed computing and communication capacities. Yet when these resources cannot adequately support inference demands, optimizing deployment alone is insufficient: the supporting infrastructure must also be provisioned. Crucially, deployment and provisioning are inherently coupled. How a DNN is partitioned determines where capacity is needed, while capacity provisioning can fundamentally change the preferred deployment. Motivated by this interdependence, we investigate the co-design of DNN deployment and infrastructure capacity for pipelined inference. Despite the coupling between these decisions, we reveal an efficiently solvable structure: on acyclic networks, the problem admits an exact shortest-path reformulation, enabling globally optimal joint design in polynomial time. Numerical evaluations demonstrate the benefits of co-design over treating deployment and provisioning separately, highlighting the potential of inference-driven infrastructure planning.

cs.NI↗

Nonparametric In-Context Learning and Inference via Measure-Indexed Kernel Ridge Regression

In-Context learning enables an estimator, trained across multiple tasks, to adapt to a new unseen task solely through its in-context samples, without any parameter refitting. Despite growing interest in the statistical foundations of in-context learning, two gaps still remain. First, existing convergence results do not characterize the distributional behavior of the in-context learning estimators. Second, classical nonparametric methods are not designed to handle the measure-valued inputs that in-context learning naturally produces. We address both gaps by developing a measure-indexed reproducing kernel Hilbert space framework, in which the adaptivity of the estimator is captured through the dependence of a mean functional on the empirical measure of the context. Within this framework, we propose a measure-indexed kernel ridge regression estimator computed from multiple independent tasks and establish its minimax-optimal convergence rate. We further prove that the proposed estimator is pointwise asymptotically normal, enabling the construction of confidence intervals for the mean and prediction intervals for the response on an unseen task. Notably, the estimator achieves valid uncertainty quantification without any refitting when adapting to a new task. As a special case, our framework recovers classical distributed nonparametric regression when all tasks share the same underlying function. The proposed framework is illustrated through a latent Gaussian process example.

stat.ME↗

IRPM: Intergroup Relative Preference Modeling for Pointwise Generative Reward Models

Generative Reward Models (GRMs) have demonstrated strong performance in reward modeling, due to their interpretability and potential for refinement through reinforcement learning (RL). However, widely used pairwise GRMs create a computational bottleneck in reinforcement learning from human feedback (RLHF), when calibrating or aggregating preference signals over n candidates, often incurring O(n^2) pairwise judgments. To address this issue, we propose Intergroup Relative Preference Modeling (IRPM), an RL-based method that extends the Bradley-Terry preference-learning paradigm via intergroup comparisons to train pointwise GRMs from pairwise preference data. IRPM derives a pointwise reward for each response by contrasting groups of chosen vs. rejected samples, enabling pointwise scores comparable across candidate sets and O(n) reward evaluation for a variable number of candidates during RL training, while preserving interpretability and scalability. Experiments show that IRPM achieves state-of-the-art performance among pointwise GRMs on JudgeBench and RewardBench, and approaches the performance of leading pairwise GRMs. In addition, IRPM achieves substantial gains in post-training evaluations, demonstrating its effectiveness. Our models and code are available at https://github.com/XINGYUN-AI-LAB/IRPM.

cs.LG↗

PSR~B0355+54: An Unexpected Compendium of Nearly All Scintillation Arc Morphologies

Scintillation arcs are sensitive probes of multipath propagation, offering a window into the distribution of scattering material in the interstellar medium. Contrary to the common observational finding that individual pulsars exhibit only a limited range of scintillation arc morphologies, we report that PSR~B0355+54, observed simultaneously at 2.25/8.60~GHz with the Shanghai Tianma Radio Telescope, displays nearly the full range of known arc patterns, many of which evolve rapidly. Across 54 observations from 2020 to 2026, we detect scintillation arcs in 53/53 usable observations at 2.25~GHz and 33/49 at 8.60~GHz. At 2.25~GHz, the secondary spectra exhibit five broad morphological types: forward arcs, inverted arclets, diffuse arcs, diffuse power, and irregular structures, with prominent displaced arclets appearing in several observations. In contrast, the 8.60-GHz spectra are generally dominated by faint forward arcs. Despite these marked morphological differences, the scaled curvatures and their annual variations agree between the two frequencies, showing that both trace the same dominant scattering screen at a fractional distance of $s=0.069^{+0.015}_{-0.014}$ near the pulsar, further supporting a possible association with the \ion{H}{ii} region Sh~2-205. Simulations show that this diversity can arise from variations in the scattered-image distribution within this screen, while brightness reconstructions at 2.25~GHz resolve localized structure down to $\sim0.02~\mathrm{mas}$. Tracking four arclets over 10~h at 8.60~GHz, including two displaced arclets, reveals a common evolutionary trend consistent with the line of sight sweeping across small-scale scattering structure, helping explain the rapid arc evolution.

astro-ph.GA↗

RealControlBench: A Benchmark for Interpretability-Informed Fine-Grained Control of LLMs and Agents

Existing steering benchmarks are built around simplified, isolated generation tasks and evaluate a single behavioral attribute under controlled settings that do not reflect the diversity and complexity of practical deployment. As a result, performance on these benchmarks provides only a limited picture of how steering methods perform in the real world. We therefore introduce RealControlBench, a comprehensive benchmark for evaluating fine-grained steering of LLMs and LLM agents across diverse behavioral targets and interaction settings. RealControlBench extends steering evaluation beyond isolated generations to complex, execution-grounded, multi-turn agent interactions, covering five complementary dimensions: instruction-following control, agentic tool-use decision control, reasoning-performance steering, reasoning-length control, and trajectory-conditioned safety awareness. Rather than measuring steering success alone, the benchmark jointly evaluates target controllability and capability preservation, including instruction following, reasoning performance, and downstream agent utility and safety. It further examines whether steering effects remain specific and robust across prompt variations, domains, and model architectures. Our evaluation shows that existing steering methods remain unreliable across realistic control objectives: they often fail to consistently induce the intended behavior and can substantially degrade the model's underlying task performance. These results suggest that strong steering effects in controlled settings do not necessarily translate into reliable control in more realistic evaluations. By providing a unified, model-agnostic steering evaluation framework, RealControlBench aims to support the development of steering methods that are not only effective but also precise, robust, and useful in realistic AI deployments.

cs.CL↗

Localization Lengths for Two-Dimensional Random Band Matrices: Stretched-Exponential Lower Bounds

We consider $N \times N$ random band matrices $H = (H_{xy})$ with centered complex Gaussian entries, indexed by points $x,y$ on the two-dimensional discrete torus $(\mathbb{Z} / \sqrt{N} \mathbb{Z})^2$. The matrix entries $H_{xy}$ vanish whenever the distance between $x$ and $y$ exceeds a constant multiple of the bandwidth parameter $W$. We prove that, for any fixed $\varepsilon>0$, if $W\geq(\log N)^{2+\varepsilon}$, then all bulk eigenvectors are delocalized with high probability. Equivalently, this yields a lower bound of order $\exp(W^{1/2-\varepsilon})$ on the localization length of two-dimensional random band matrices for arbitrarily small constant $\varepsilon>0$, improving the superpolynomial lower bound $W^C$ for every fixed constant $C>0$ established in arXiv:2503.07606. A key ingredient of our proof is a new strategy that closes the resolvent flow analysis using only loop observables of order at most two, without relying on the higher-order loop hierarchy.

math.PR↗

Rep2Text: Decoding Full Text from a Single LLM Token Representation

Large language models represent text as hidden numerical patterns, but what information these representations actually contain remains a mystery. Can we recover the original text from just one of them? In this paper, we introduce Rep2Text, a method designed to answer this question by reconstructing text from a single hidden representation. We find that these representations preserve much more information than we might expect. For short texts of about 16 words, Rep2Text can recover roughly half of the original words while preserving their overall meaning. As the text gets longer, recovering the exact wording becomes harder, but the main ideas can still be recovered. These findings offer a new way to understand what language models store internally and highlight potential privacy risks, as hidden representations may reveal parts of the original input.

cs.CL↗

Workplace Ambiguity and Technology Support for Autistic and IDD Workers

Workplace ambiguity, where expectations, evaluations, or procedures are left unstated, acts as a structural access barrier for autistic and IDD workers, routinely forcing them to act on guesses. To investigate how these barriers operate, we interviewed 11 caregivers, concluding with an AI co-design activity to explore technological solutions. Their perspectives revealed five themes of workplace ambiguity, which we synthesize into a conceptual framework comprising three intersecting dimensions: evaluative, procedural, and relational. To address these barriers, participants proposed three forms of technology support, including ambient real-time redirection, feedback processing, and physiological guidance, designed to make hidden expectations perceptible and actionable. However, this exposes a core tension: technologies designed to make the workplace legible can inadvertently make the worker hyper-legible to employers through surveillance. We argue that ambiguity-aware workplaces must make expectations explicit before they carry consequences, and assistive technologies must remain accountable to the worker.

cs.HC↗