Software Engineering
Rust's Type Checker Implementation Is Unsound: An Empirical Study on Soundness Bugs in rustc
Yusung Sim, Sukyoung Ryu and Jaemin Hong
Rust is claimed to be a type-sound
language capable of preventing various undesirable behaviors, including
memory bugs. However, rustc, the official Rust compiler, is not immune to defects; it contains soundness bugs, where the compiler accepts programs that should be rejected during type checking. In this work, we present an empirical study of 30 issues that report potential soundness bugs in rustc, collected from the GitHub issue tracker between January 1, 2022 and September 1, 2025. We analyze each issue in depth, focusing on its affected feature, symptom (how the feature is mishandled), consequence (the resulting undesirable behavior), triggering features, community consensus regarding whether it is a bug, and lifecycle, including introduction, discovery, and fix. Furthermore, we investigate existing artifacts, including implementations such as AddressSanitizer, Miri, Chalk, and a-mir-formality, alongside documentation such as the Rust Reference, the FLS, and Rust RFCs to assess their potential as oracles for testing the type soundness of rustc. Our key findings indicate that: (1) Certain soundness bugs, typically triggered by implied bounds or trait objects, compromise
memory safety. (2) Sound type checking is challenged by edge cases involving associated types and the interaction between lifetimes and traits. (3) Most bugs persist from the initial introduction of the relevant features and require significant time to be discovered. (4) While AddressSanitizer and Miri can detect soundness bugs that lead to
memory bugs, a-mir-formality and Chalk are currently immature despite their potential to identify other bug categories. (5) Existing documentation frequently fails to provide precise explanations of the
language semantics.
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Computer Vision · Cross-listed from eess.IV
Coronary Mask Guided Registration for Continuous Time 4D Cardiac CT Dataset Construction
Yuang Wang, Shuo Wang, Changyu Chen et al. (+12 more)
Objective: Clinical cardiac CT multiphase reconstructions generally provide acceptable image quality in end-diastole (ED) or end-systole (ES) phases, but in other phases may exhibit motion artifacts, especially in the right coronary artery (RCA). This limits ground-truth availability in 4D cardiac CT imaging research. We aim to construct a 4D cardiac CT
dataset that is generally suitable to serve as pseudo ground truth. Methods: We propose Coronary Mask Guided Registration (CMGR) to produce a motion-preserved, artifact-reduced, and continuous-time 4D cardiac CT sequence from the clinical multiphase reconstruction of each patient. For artifact reduction, CMGR uses the ED or ES phase as the reference phase and warps the reference volume with deformation fields to produce the sequence. For motion preservation, CMGR registers the reference phase to each non-reference phase of the multiphase reconstruction. To capture the motion of both the RCA and other cardiac structures in each registration, CMGR regularizes RCA masks and incorporates them into image-domain registration. Time-continuity is achieved by interpolating the deformation fields for non-reference phases to arbitrary times. Results: CMGR outperformed representative image-domain registration methods in capturing RCA motion and providing reasonable RCA shape, and showed competitive performance in capturing whole-heart motion. Additionally, CMGR reduced motion artifacts from clinical multiphase reconstructions, and intermediate CMGR frames generally provided plausible transitions between discrete cardiac phases. Conclusion: CMGR provides an effective approach for constructing continuous-time 4D cardiac CT
datasets. Significance: The
dataset can be used in system design simulations and in reconstruction
algorithm development, thereby facilitating advances in cardiac CT imaging.
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All authors Yuang Wang, Shuo Wang, Changyu Chen, Dufan Wu, Pengfei Jin, Yunqiang An, Yang Gao, Bin Lu, Dongrui Dai, Muge Du, Yan Yan, Dong Li, Liang Li, Li Zhang, Zhiqiang Chen
Machine Learning
QGPINNs: A Physics-Informed Neural Network Framework for Nonlocal Differential Equations on Quantum Graphs
Vaibhav Mehandiratta and Saket Ramchandra
We propose QGPINNs, a physics-informed neural network framework developed in PyTorch for the numerical solution of nonlocal differential equations on
quantum graphs. The framework is designed as a general computational implementation in which the solution on each edge of the graph is approximated by a neural network, while a unified graph-based loss function enforces the governing equations together with initial, boundary, and vertex transmission conditions. In particular, the formulation incorporates standard continuity and Kirchhoff-Neumann vertex conditions and Dirichlet boundary conditions into the learning process to couple the local edge-wise neural approximations into a global solution on the graph. The framework is developed for two representative classes of nonlinear models: multi-order fractional
elliptic problems and time-fractional
evolution equations on
quantum graphs. To improve accuracy and training stability, QGPINNs integrates several graph-adapted learning strategies, including soft and hard constraint enforcement, dynamic loss balancing,
Fourier feature
embeddings, and a learnable singularity-capturing feature for weakly singular solutions arising in the considered problems. The framework also extends naturally to inverse problems, including the identification of the orders of fractional operators and physical parameters from noisy observational data. We validate the accuracy, computational efficiency, and physical consistency of the proposed framework through numerical experiments on
benchmark graph structures and real-world networks, including the IEEE 14-bus system and an open-channel agricultural drainage network.
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Robotics
Aero Hand Open: A Simulation-Ready Tendon-Driven Hand for Dexterous Manipulation Learning
Nan Wang, Mohit Yadav, Jonathan Wulff et al. (+5 more)
Tendon-driven hands are anthropomorphic, and moving the actuators off the joints is what makes a hand of this capability affordable to build. Two effects produce that saving. Routing force through a cable removes the requirement that a motor fit inside the joint it drives, so smaller and cheaper motors suffice, and one motor can drive several joints through a single cable, so fewer motors are needed. They are also harder to learn on than a direct-drive hand. The underactuated transmission that produces the saving is itself difficult to represent in a simulator, and the joints one cable drives are not independently commandable. We present Aero Hand Open, a tendon-driven anthropomorphic hand that is released simulation-ready. Three things ship with it. A simulation model reproduces the cable transmission itself. An identified actuation map connects that model to the motor commands in both directions, including the three-way coupling of the thumb. A reinforcement learning package trains policies for the hand. Together they let a policy be trained entirely in simulation and run on the hand with no fine-tuning and no state estimation. We release the mechanical design, the simulation model, the identified mapping, the training environment and the deployment stack.
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All authors Nan Wang, Mohit Yadav, Jonathan Wulff, Aidan Rosenbaum, Kezhou Chen, Yuvan Sharma, Xu Dong, Yiwei Tao
Artificial Intelligence · Cross-listed from stat.ME
Learning a Size-Weight Frontier for Synthetic-Augmented Inference
Chengpiao Huang and Kaizheng Wang
Synthetic data can improve statistical inference when real data are scarce, but naively treating synthetic samples as real data can introduce bias and lead to unreliable inference. We develop a general framework for synthetic-augmented inference across a population of related tasks. It characterizes synthetic augmentation by the number of synthetic observations and their weight. Central to our framework is a size-weight frontier that specifies, for each weight, the largest synthetic sample size for which all smaller sizes attain the target task-marginal coverage. We estimate this frontier from historical tasks, and establish a finite-sample coverage guarantee simultaneously for all size-weight configurations on or below the estimated frontier. In experiments using large
language model responses to augment opinion survey data, our procedure achieves target coverage and substantially narrows confidence intervals.
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Information Retrieval
PULSAR: Pooled Unified Late-Interaction Search and Retrieval for Enterprise Visual Document RAG
Benjamin Constable, Anup Roy, Vishal Sharma et al. (+3 more)
Institutional investors search visually dense pitch decks, board packs, and diligence materials that change hourly near deal closing. OCR followed by figure verbalisation is costly to refresh at this scale and can lose chart detail. We present
PULSAR, a production
vision-first
retrieval system deployed at Mubadala Investment Company.
PULSAR indexes page images with a frozen ColPali-style backbone and uses a pooled two-stage late-interaction index: compact page summaries support initial
retrieval, followed by exact MaxSim rescoring over a finer pooled representation. On ViDoRe V3, this design reduces median vector-search latency by 15.1 times against an unpooled configuration with less than 0.01 absolute NDCG@10 and Recall@10 loss; production median vector-search latency is 156 ms. Under concurrent load, the pooled index sustains approximately 88 times higher QPS than an unpooled index. The event-driven ingestion path is estimated to be approximately 20 times cheaper per page than the OCR+verbalisation baseline it replaced. Since March 2026,
PULSAR has served 78 thousand documents and approximately 2.4 million pages across more than 3,000 deals. At the production top K, it more than doubles answer-fact recall over the OCR+verbalisation baseline.
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All authors Benjamin Constable, Anup Roy, Vishal Sharma, Rishabh Upadhyay, Robin Mills, Aidan Millar
Robotics
ChainSplat: A Physics-Inspired Screw-Theoretic Model for Learning Deformable Linear Object Dynamics from Multi-View RGB Videos
Seungyeon Kim and Noémie Jaquier
Identifying the underlying dynamics and 3D geometry of deformable linear objects (DLOs), such as cables, ropes, and hoses, is essential for accurate robotic manipulation, but remains challenging due to their high-dimensional configuration spaces and diverse behaviors arising from varying material properties. Existing methods often rely on multi-stage pipelines and auxiliary depth inputs, which are prone to errors under dynamic interactions, while their high-dimensional state representations make model-based control computationally expensive. In this paper, we introduce ChainSplat, a physics-inspired framework that jointly learns the 3D geometry, appearance, kinematics, and dynamics of DLOs solely from multi-view RGB
videos. ChainSplat represents a DLO as an open-chain structure of rigid links connected by revolute joints, yielding an analytic, screw-theoretic model with a compact state representation parameterized by joint configurations. By integrating this formulation with Gaussian splatting, ChainSplat jointly recovers DLO dynamics, kinematics-aware 3D geometry, and appearance, while enabling high-fidelity RGB rendering from arbitrary states. Through real-world experiments, we demonstrate that ChainSplat achieves state-of-the-art performance in dynamics predictions, 3D geometry reconstruction, and RGB rendering across dynamic interactions. ChainSplat further enables real-time state and force estimation, as well as accurate model-based trajectory optimization, highlighting its practical utility for real-world robotic manipulation of DLOs. Accompanying source code and
video are available at: https://chainsplat.github.io.
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Computer Vision
SignRR: Retrieve and Refine Real Motion for Sign Language Production
Fidel Omar Tito Cruz, Angie Sanchez Marquina, Summy Farfan et al. (+1 more)
Sign
language production (SLP) aims to generate continuous signing motion from spoken
language, often through gloss-to-pose generation. Prior work mainly follows two paradigms. Generative models synthesize motion from a learned prior or from noise, without reference to an observed signing instance, making rare hand configurations and signer-specific articulation difficult to preserve.
Retrieval-based methods reuse real, well-articulated motion segments, but concatenating segments from different signers and co-articulation contexts can introduce rhythm and style inconsistencies across the full sequence, not only at segment boundaries. These limitations suggest a complementary solution: use
retrieval to provide realistic articulation, and use learned refinement to impose the global coherence that
retrieval alone lacks. We therefore propose retrieve-and-refine, a paradigm that starts from real retrieved motion and refines it into a globally coherent signing sequence rather than generating motion from scratch. Our framework, SignRR, initializes motion from a dictionary of real sign segments and refines the full sequence with a part-aware Residual VQ-VAE, where residual quantization preserves fine hand articulation and temporal length differences are handled in the latent space. Experiments on PHOENIX14T and CSL-Daily show that SignRR achieves state-of-the-art back-translation performance while maintaining competitive pose quality.
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All authors Fidel Omar Tito Cruz, Angie Sanchez Marquina, Summy Farfan, Gissella Bejarano
Computer Vision
GeBDA: Building Damage Assessment as Text-Based Sequence Prediction
Olivier Dietrich, Krishna Sapkota, Konrad Schindler et al. (+1 more)
Conventionally, Building Damage Assessment (BDA) is tackled either with dedicated network architectures or by fine-tuning geospatial image foundation models. In this work, we ask whether a general-purpose
Vision-
Language Model (VLM) can localize buildings and grade their damage through autoregressive sequence generation alone. We cast BDA as predicting a variable-length set of bounding boxes, each specified by its coordinates and a damage label. Our preliminary implementation, based on the open Gemma model, achieves promising damage mapping results from only bi-temporal satellite images and a suitable text
prompt.
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All authors Olivier Dietrich, Krishna Sapkota, Konrad Schindler, Genady Beryozkin
Data Structures and Algorithms
On two proofs of $d^2$ mixing of weighted Dikin walks
Yuansi Chen and Yunbum Kook
We study the mixing time of weighted Dikin walks for sampling from exponential distributions on polytopes and truncated positive-semidefinite (PSD) cones. Our first result gives a general total-variation mixing bound under strong self-concordance, $\bar{\nu}$-
symmetry, and mixed-trace regularity on the local metric. The key idea is to control the Metropolis–Hastings acceptance probability on a high-probability region rather than at every point. Applying this framework to the Lee–Sidford, Lewis-weight, and John metrics yields an $\widetilde O(d^2)$ mixing bound for sampling from polytopes, while applying it to a hybrid barrier yields an $\widetilde O(d^4)$ mixing bound for sampling from truncated PSD cones. Our second result establishes stronger $\chi^2$-divergence guarantees and pointwise acceptance control using a new fourth-order bootstrap condition. For a suitably scaled Lee–Sidford metric, this yields an $\widetilde O(d^2)$ mixing bound in $\chi^2$-divergence, improving on the previous $\widetilde O(d^{9/4})$ bound.
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Machine Learning · Cross-listed from stat.ML
Learning between the peaks: sharp asymptotics for kernel ridge regression under power-law anisotropy
Lorenzo Rizzi, Arie Wortsman Zurich and Bruno Loureiro
We study kernel ridge regression under anisotropic Gaussian data, where the input covariance decays as a power law with exponent $\alpha\geq 0$ for
polynomial inner-product kernels. We derive asymptotically sharp expressions for the kernel spectrum and the generalization error in the
polynomial high-dimensional regime $n=\Theta(d^\kappa)$, revealing how anisotropy reshapes the learning curves. For weak anisotropy ($0<\alpha<1$), the problem remains effectively high-dimensional and retains some features of the isotropic case, while departing from it in others: the variance still peaks at integer sample complexities $\kappa\in\mathbb{N}$, but these peaks are progressively damped as $\alpha$ grows; meanwhile, for targets strongly aligned with the data's principal directions, the bias drops at fractional sample complexities, decoupling the bias transitions from the interpolation peaks. For strong anisotropy ($\alpha > 1$), the effective dimension of the problem is constant, and the variance stops depending on sample size altogether, plateauing under ridgeless interpolation or vanishing at an explicit rate under fixed ridge penalty. The bias undergoes a sharp transition governed by the target's decay rate: below a threshold, learning is abrupt rather than gradual; above it, the bias decays as a power law that recovers the classical source and capacity rates. We finally specialize these results to single-index targets, showing how the
alignment of the index with the data's principal directions determines the effect of anisotropy on learning. Together, our results clarify how the input geometry shapes the kernel features and fundamentally impacts its generalization properties.
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Computation and Language
A Formal Limitation on Learning Human Language From Textual Corpora
Emily Cheng and Ryan Cotterell
Can a listener recover what a speaker means from the form of an utterance alone? We answer this question information-theoretically, and for a listener given by any featurizer of text, including the hidden states of contemporary large
language models. Modeling
language use as a joint distribution over meanings, contexts, and utterances, we derive upper bounds on the probability that a decoder recovers a speaker's intended meaning from a representation of the utterance. The bounds are governed by the uncertainty that form leaves about meaning, which splits into an irreducible part and a part that only (extralinguistic) context, but never the utterance alone, can resolve. Because these quantities are intrinsic to
language, no representation, however much text or supervision produced it, can surpass them. The bounds apply, moreover, to meaning spaces that are discrete or continuous. We provide empirical evidence in support of the theory through experiments on artificial
languages, Mandarin zero-pronoun resolution, and color reference.
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Machine Learning
Blog: Survey of Optimizers
Ruoran Xu
Neural-network optimization in 2025-2026 is no longer well described as a succession of new Adam variants. The design space has expanded from coordinates to
matrices and layers, from fixed training horizons to policies over time, and from mathematical update rules to state representations that must survive sharding and low-precision computation. This survey organizes recent optimizers and training optimization methods along four largely independent axes: temporal estimation, update geometry, horizon management, and representation and systems. It connects the spectral normalization of
Muon, the historical
matrix statistics of Shampoo and SOAP, adaptive and hybrid
matrix methods,
memory-efficient optimizers, schedule-free training, small-batch corrections, and quantized optimizer states. The central empirical conclusion is deliberately non-triumphal:
matrix-aware methods represent a genuine advance, but there is no context-independent replacement for AdamW. Rankings change with model scale, data-to-parameter ratio, batch size, schedule, parameter partition, tuning budget, and whether the target metric is
tokens, FLOPs, wall-clock time, or
memory. The practical consequence is a compositional view of optimizer design and a stricter protocol for evaluating optimizer claims.
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Information Theory
A Complete Characterization of Tensorizable $f$-divergences
Rodrigo Cruz, Flavio P. Calmon and Qian Yu
Csiszar's formulation of the $f$-divergence introduced a vast family of functionals for quantifying dissimilarity between probability distributions. However, many applications in statistics and information theory rely only on a few $f$-divergences, such as the Kullback-Leibler divergence, the $\chi^2$-divergence, and the squared Hellinger distance. These divergences are especially useful because they admit simple compositional formulas under product measures, a property sometimes referred to as tensorization. In this work, we refine a formalism of tensorization previously introduced in the literature. Then, we show that any possible tensorization formula has a multi-affine form characterized by a single parameter, and identify all tensorizable $f$-divergences under our adopted notion of tensorization.
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Information Retrieval
QUEST: A Query and Extraction System for Topics in Asylum Law Application Decisions
Maria Vlachou, Anna Murphy Høgenhaug, Mohammad N. S. Jahromi et al. (+4 more)
Legal decisions on asylum applications consist of long, complex, and heterogeneous documents, covering narrative applicant interviews, original decisions, and additional supporting materials. If an application is rejected, a critical question in processing an appeal is whether the credibility of the information in the original application was a factor that determined the original decision. In this paper, we present the QUEST system (Query and Extraction System for Topics) to extract and identify factors relating to credibility assessments in two
datasets of Danish asylum application appeals. QUEST frames this problem as an information
retrieval task, combining synthetic query generation, topic extraction, and relevance assessment to identify information related to credibility indicators in appeals board application materials. In addition to standard
retrieval evaluation metrics, we propose a new type of domain-specific assessments distinct from the traditional relevance to evaluate the performance of the tested systems with respect to credibility factors. In this way, we obtain insights about how well automatic methods can return answers for different types of indicators appearing in asylum appeals. Our results indicate that there is an increased challenge when estimating performance using credibility-based relevance assessments, thus pointing to the difficulty of the task.
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All authors Maria Vlachou, Anna Murphy Høgenhaug, Mohammad N. S. Jahromi, Galadrielle Humblot-Renaux, Thomas Gammeltoft-Hansen, Thomas B. Moeslund, Desmond Elliott
Artificial Intelligence
Composition without a Host: Carrying the Spatiotemporal-Composability Guarantee of Plugin-Based Agents across Processes
Hanzhang Jia, Liheng Zeng, Hao Cheng et al. (+3 more)
Plugin-based
agents assemble capabilities at runtime, and the spatiotemporal-composability calculus proves a reversibility guarantee for this assembly. However, the guarantee is carried by a single process, which confines all components, sessions, and recovery records to one failure domain, where a fault spreads past the plugin boundary, and process death interrupts every session the process hosts. Resting only on the hypotheses the calculus already states and the stateless interface of the model call, this paper relaxes the single-process restriction of the calculus to an arbitrary assignment of components and records to processes, gives four sufficient conditions, and proves with
Theorem 1, derived from the four lemmas, that the reversibility guarantee holds across processes when these conditions are met. Based on
Theorem 1, this paper constructs Logos, a cross-process plugin-based
agent in the peer-process and name-routed form of ROS, where a plugin is a process, the router holds only a rebuildable routing table, and the session state needed for recovery lives in an append-only transcript owned by no process. Under one fault on two hundred
benchmark tasks across three configurations, the single-process reference lost every session and scored 1.5 percent on the official validator, the MCP configuration kept its sessions while spending 1099 calls on a dead endpoint, and Logos kept every session alive, wasted zero calls, and succeeded on 120 tasks against 102 for both configurations combined. At the mechanism level, eighty sessions terminated at four points of the tool-call cycle all resumed with no repeated action, 3,500 concurrent calls paired with zero violations, and one bus hop cost 1 in 823 of the model's first
token. The results show that the reversibility guarantee holds across processes and that assembly itself can leave the host process.
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All authors Hanzhang Jia, Liheng Zeng, Hao Cheng, Yi Gao, Bo Ma, Guolong Xu
Machine Learning
Advancing Interaction-Sensitive Feature Selection: Novel Relief-Based Algorithms, Expanded Comparisons, and Recommendations for Biomedical Data Mining
Kia Kazemi-Nia, Harsh Bandhey, Philip J. Freda et al. (+1 more)
As a precursor to high-dimensional biomedical data modeling, reliable feature selection can reduce computational expense, improve modeling performance, and yield simpler, more interpretable models. However, most filter-based feature selection methods struggle to detect feature interactions, while wrapper or embedded feature selection methods are computationally expensive. Relief-based
algorithms (RBAs) are filter methods that are sensitive to feature interactions while mitigating these other limitations. This study (1) refactors, optimizes, and expands the scikit-rebate Python package with existing and newly proposed RBA variants and (2) conducts rigorous RBA
benchmark comparisons across diverse genomic simulations. We expand scikit-rebate to include SWRF*, mu-Relief, and 5 novel RBA variants implementing alternative strategies for neighbor selection and feature scoring. All RBAs were evaluated to compare predictive feature ranking and runtime across simulated genomic
datasets varying in sample size, number of features, heritability, and underlying association type (e.g. main effects and interactions). All RBAs, except mu-Relief, were proficient in detecting 2-way interactions in noisy data. RBAs utilizing 'far' scoring were best at detecting 2-way interactions - with MultiSWRFDB* top-performing - but were far less sensitive to main effects. SWRF, MultiSWRF, MultiSURF, and MultiSWRFDB yielded top performance across main effect and 2-way interaction
datasets with MultiSWRFDB performing best when also considering 3-way interactions. Refactoring of scikit-rebate resulted in 10 to 35-fold reductions in RBA runtimes. The newly introduced RBAs were among the strongest performing, and by robustly retaining both main effects and 2-way epistatic interactions, these
algorithms preserve predictive signals for downstream modeling.
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All authors Kia Kazemi-Nia, Harsh Bandhey, Philip J. Freda, Ryan J. Urbanowicz
Computer Vision
Video Generative Models as Geometry Learner
Haosen Yang, Jifei Song, Zhensong Zhang et al. (+2 more)
Recent generative approaches to geometry estimation adapt pretrained image
diffusion models and treat the task as image-conditioned generation. Leveraging off-the-shelf image
diffusion models, they either (i) train task-specific geometry models (for depth and surface normal estimation) independently, losing the opportunity of exploring the intrinsic correlation of these
geometric targets, or (ii) jointly fine-tune modified image
diffusion backbones (e.g., altered self-
attention), which typically demands substantial labeled data. To overcome these limitations in a principled fashion, we repurpose pretrained
video generative models as a unified and data-efficient framework for geometry estimation, formulated innovatively as a next-frames prediction task. Our method, GeoNeXt, inherits naturally structured knowledge and richer priors from the
video model, while further adapting them for joint modeling of images and geometry targets (image <-> geometry), enabling more data efficient and effective learning of geometry. Extensive experiments validate our method for zero-shot
monocular depth and surface normal estimation across diverse
datasets, outperforming both previous task-specific and unified generative competitors while using substantially less training data. Notably, our method rivals discriminative state-of-the-art approaches trained on over 100x more data and even standouts on several
benchmarks.
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All authors Haosen Yang, Jifei Song, Zhensong Zhang, Xiatian Zhu, Jiankang Deng
Machine Learning
DARTS: Decoder-Aware Representation Tuning via Surgery for Model Merging
Aaryan Ajay Sharma, Sai Nishanth Padala and Seganrasan Subramanian
Model merging combines multiple task-specific fine-tuned LLMs into a single multi-task model without additional training. However, merged models are known to suffer from representation bias: systematic drift between the merged model's hidden states and those of each individual source model. Prior work (Yang et al., 2024a) study and mitigate this bias for encoder-based
vision models using a lightweight correction module trained with L1 loss. However, such bias is not studied for decoder models due to their autoregressive nature. We analyze the problem of representation bias in decoder models, and show two challenges absent in encoders: (1) the causal
attention mask causes bias to accumulate across
token positions, requiring position-dependent correction; and (2) not all
token positions are equally important, i.e., high-
entropy (decision-critical) positions matter far more than low-
entropy ones. To address these challenges, we propose Decoder-Aware Representation Tuning via Surgery (DARTS). DARTS employs a novel
entropy-weighted L1 loss to upweight correction at high-
entropy positions where errors most affect generation quality, and a per-position additive bias that captures position-dependent error without overparameterization. We perform extensive evaluation on three domains: code generation (HumanEval), mathematical
reasoning (GSM8K), and instruction following (AlpacaEval) on Llama-2-7B models, and show DARTS achieves significant improvement over the standard surgery approach while adding negligible parameters ($0.1\%$ of total parameters).
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Numerical Analysis
Closest Normal Matrix Found Again Using Riemannian Optimization
Vanni Noferini and Matvei Zhukov
We propose an approach based on Riemannian optimization to compute a nearest normal
matrix to a given one. The problem can be formulated as the minimization of a smooth function either on the
manifold $U(n)$ of
unitary matrices of size n or on the flag
manifold $U (n)/U (1)^n$. The flag
manifold is particularly suitable for theoretical analysis; we characterize the global maximum of the objective function and prove that, for generic inputs, its local minimizers are finitely many and isolated; in turn, this implies the original nearest normal
matrix problem generically has finitely many local minimizers, all with distinct
eigenvalues. We also develop a Riemannian trust-region method that improves substantially on classical
algorithms and can handle considerably larger
matrices, as well as a variant for computing the nearest real normal
matrix. The paper is complemented by extensive numerical experiments.
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Cryptography and Security
Policy-Controlled Offline-Verifiable Accountability for Cross-Organization Agent Messaging: A Preserved Evidence-Bundle Approach
Adil Alshammari and Hayretdin Bahsi
Cross-organization
agent workflows require preserved evidence that remains independently verifiable during later audit or dispute review. Such workflows may involve multiple organizations, delegated actions, policy-relevant events, and disputed accountability claims. This is difficult when live systems are unavailable, controlled by one party, or not trusted by all participants. Existing mechanisms provide useful pieces, including authenticated logging, delegation semantics, signed checkpoints, and consistency checks. What remains missing is a verifier-centered event-level bundle for checking evidence sufficiency offline under an explicit policy. We propose a preserved evidence-bundle model and a policy-controlled offline verifier for
agent-to-
agent workflow events. Each bundle preserves policy-required evidence, including sender authentication, authenticated log commitment, witness-backed checkpoint evidence, append-only continuity, delegation-aware authorization evidence, and, when issued and required by policy, explicit receiver-signed receipt evidence. The verifier accepts a bundle only when all mandatory and policy-required checks succeed, giving a later dispute reviewer an offline basis for assessing evidence sufficiency. It does not infer delivery or receipt from transport behavior or log inclusion alone. In a prototype evaluation, the event-type study used 300 synthetic four-event healthcare workflow cases and 1200 valid preserved bundles. The policy-profile comparison observed its largest median latency reduction relative to the fully enabled profile when checkpoint-context validation was disabled. All 17 tested cases in the original negative-evidence diagnostic suite were rejected under the fully enabled profile. Additional functional studies examined context and signed-reference binding. These results support prototype feasibility for the evaluated workloads.
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Machine Learning
An Enclosed Mode Is a Gauge Choice: Topology Relative to Reach in Certified Code World Models
Javier Aguilar Martín
A code world model accepted by a sampling gate can be exactly right on everything the gate can see and arbitrarily wrong beyond it. We characterize what a certified model can know, and what its errors can cost, when the omission is an annular freeze mode enclosing an unreachable interior. The gate quotient makes the question precise: acceptance-with-certainty determines the model exactly on the reachable query set; beyond reach is gauge. On a minimal ring instrument we prove the extreme case (a wrong-
topology filled-disc artifact unfalsifiable by any sampling gate and bitwise harmless at play) and measure, with LLM synthesis across three model families, how one knob (a channel of width gamma) walks the same artifact through three regimes: unfalsifiable-and-harmless, falsifiable-and-costly, and instantly falsified. Three principles organize the empirics. First, danger is
topology relative to reach: a channel the planner can use collapses the blind model's exploitation (play cost 1.09 to ~0 over a knee at gamma ~ 0.1), while a hidden channel with the same first Betti number keeps it at full strength (1.12). Second, repair is parameter-bound and sensor-bound: no family recovers the region from outside evidence; from inside, models pose the right
topology but cannot pin its parameters, and the posed
topology tracks the guiding persistent-homology summary's wrong beta_1 (a sensor with a measured
geometric resolution limit), not the truth. Third, mitigation must match the error's dimension and direction: point fences fail against the one-dimensional boundary, a dimension-matched persisted fence collapses exploitation to a two-lesson transient (0.999 to 0.058), and the dual freedom certificate collapses the invented-mode failure symmetrically (1.769 to 0.029). In n dimensions the shell makes misidentification near-certain while the danger stays fully exploitable: the two axes are independent.
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Computational Complexity · Cross-listed from math.CO
Analysis of Polynomial Threshold Functions on Random Regular Graphs: Computational Complexity of Detecting Noisy Random Lifts
Xifan Yu
In this work, we present the first analysis of low-degree
polynomial threshold functions for the natural hypothesis testing problem of detecting the noisy random lift of a base $d$-regular graph from a uniformly random $d$-regular graph. Along the way, we obtain a new result for the distribution of short cycle counts in noisy random lift up to logarithmic lengths, which generalizes results by McKay, Wormald, and Wysocka and by Johnson in the case of random regular graphs, and results by Greenhill, Janson, and Ruciński and by Fortin and Rudinsky in the case of random lifts.
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Artificial Intelligence
InstructMesh: Selective Refinement of Generative 3D Models for Fabrication
Faraz Faruqi, Ahmed Katary, Demircan Tas et al. (+10 more)
Recent advances in generative AI allow users to create 3D models from text or images. However, these models prioritize visual plausibility over
geometric accuracy, often generating results with flaws that compromise their intended use post-fabrication. We present InstructMesh, an interactive post-generation refinement tool that enables selective repair of generative 3D models through region selection and targeted operations, such as opening or sealing voids, or adjusting local thickness. Users can invoke edit operations via natural
language prompts or slider controls. By operating directly on the intermediate latent representation, InstructMesh allows users to apply robust
geometric corrections without requiring expert modeling skills. To inform our design, we first analyze common fabrication-related failure modes in outputs from state-of-the-art generative tools. We then conduct two user studies, demonstrating that novices can identify and perform fabrication-relevant repairs on generative outputs using InstructMesh, and revealing user preference for hybrid interfaces that combine slider controls with natural
language input.
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All authors Faraz Faruqi, Ahmed Katary, Demircan Tas, Theresa Hradilak, Ning Zhang, Jiaji Li, Fabian Manhardt, Martin Nisser, Vrushank Phadnis, Ruofei Du, Federico Tombari, Megan Hofmann, Stefanie Mueller
Systems and Control
Targeted Power System Frequency Attack via the Selection of Maliciously Controlled Inverters
Xiangyu Zou, Betelihem Ashebo and Daniel K. Molzahn
This paper studies how an adversary can execute a power system frequency attack by choosing the most effective subset of inverter-based resources (IBRs) as malicious control nodes. During the attack, the adversary controls the attacking devices to destabilize a group of designated target generators. The attack is designed by introducing an unstable oscillatory mode whose eigenvector has large components at the target generators and small components at the compromised IBRs. We formalize the optimal attacker selection problem and present an equivalent mixed-integer quadratically constrained program (MIQCP). To address this combinatorial nonconvex problem, we develop two heuristic
algorithms by introducing a ranking metric. The attack process is demonstrated on a modified WSCC 179-bus system, with results verified through nonlinear dynamic simulations. We show that the proposed heuristics find optimal attacking sets in a majority of evaluated scenarios while significantly reducing the required computational time. Scenarios from the ACTIVSg500 system are used to further support our results. Finally, we discuss how selecting different
eigenvalues, targets, and numbers of compromised devices impact the attack's severity.
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Networking
xTRUCE: A Provably Safe Arbiter for Multi-xApp Conflict Mitigation in Agentic O-RAN
Le Xia, Rose Qingyang Hu, Paul S. Kudyba et al. (+2 more)
The open
radio access network (O-RAN) is evolving toward agentic operation, where large
language model (LLM)-driven xApps/rApps generate control proposals under operator intents. However, such proposals may be conflicting, infeasible, or hallucinated, and no existing system jointly provides proposal-independent safety, priority-aware reconciliation, and traceable feedback. To this end, we propose a provably safe arbiter, namely xTRUCE, in the near-real-time (Near-RT) RAN intelligent controller for mitigating multi-xApp conflicts in gNB control. We first develop a structured xApp proposal interface and a three-layer constraint hierarchy that places physical limits and operator-defined rules above relaxable performance targets, alongside a dual-timescale control action space. A two-stage arbitration mechanism then minimizes target shortfalls in the operator-priority order to finalize safe E2 actions within the Near-RT latency budget, while returning conflict certificates to xApps and the operator for renegotiation. Finally, we implement xTRUCE in a multi-
cell O-RAN use case, and evaluate its multi-process prototype through simulations with live API-backed LLM xApps and over-the-air experiments on OpenAirInterface/FlexRIC-based O-RAN stacks. Results show that xTRUCE ensures gNB control safety with $100\%$ protected services despite severe proposal
hallucinations, achieves priority-consistent performance satisfaction under overload, efficiently guides LLM intent renegotiation via certificates, and keeps a delay-safe E2 control loop.
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All authors Le Xia, Rose Qingyang Hu, Paul S. Kudyba, Zhenlin An, Haijian Sun
Cryptography and Security
Relaxed Sender Anonymity for CBDC Interbank Settlement: A Zero-Knowledge Approach on Permissioned EVM
Pietro Tiberi, Gabriele Marcelli and Vitangelo Lasorella
Central Bank Digital Currency (CBDC) interbank settlement systems operating on Distributed Ledger Technology (DLT) face a fundamental trade-off: blockchain transparency enables trustless verification but exposes commercially sensitive bilateral transaction flows to all network participants. We propose a confidential interbank settlement protocol for permissioned Ethereum-compatible networks that resolves this tension through a relaxed sender anonymity model tailored to regulatory AML/CFT requirements. In this model, the initiating institution remains publicly identifiable on-chain for accountability and compliance, while the receiving institution, transfer amount, and business payload are cryptographically obfuscated. We realize the protocol on Hyperledger Besu using QBFT consensus, combining Groth16 zero-knowledge proofs over BN254, Poseidon hash commitments in an incremental Merkle tree, multi-recipient ECIES payload encryption, and an on-chain NoteRegistry contract that stores encrypted notes as an append-only ledger log, eliminating trusted off-chain custody servers. The protocol supports shield, confidential transfer, and unshield state transitions. Experimental evaluation across a five-node network (three commercial banks, a central bank operator, and a securities depository) demonstrates end-to-end settlement in 8-16 s, proof verification overhead of about 1 ms (around 220k gas) via EVM precompiles, and client proof generation in 4-12 s on commodity ARM hardware. While receiver confidentiality is established at the protocol level, the current proof-of-concept NoteRegistry uses owner-indexed events, a trade-off addressable in production via uniform event broadcasting.
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Social and Information Networks
Understanding Venture Capital Syndication in Information Technology Sectors: A Network Formation Perspective
Liheng Tan, Zhengkai Tu and Prasanna Karhade
Venture capital syndication enables investors to pool diligence, share risk, and signal venture quality, while shaping the relationships through which investment networks develop. We examine how prior relationships, network embeddedness, and organizational similarity structure annual co-investment link formation in U.S. information technology venture finance. Using dyad-complete PitchBook panels for the hardware, software, and hybrid subsectors from 1966 to 2024, we test seven mechanisms through full-sample dyadic logit models with dyad-clustered standard errors. Across subsectors, prior collaboration is the most consistent correlate of co-investment; shared partners, geographic proximity, and organizational-type similarity are also positively associated with link formation, while domain overlap, prominence, and experience vary across settings. A static ERGM of the 2024 software network among 1,100 persistently active investors likewise produces positive estimates for triadic closure and geographic homophily and a smaller positive estimate for type homophily. By combining complete dyadic risk sets with a whole-network specification, the study shows how relational persistence, network closure, and homophily jointly structure IT venture syndication networks. In future work, we will extend the analysis with temporal network models, counterfactual simulations of
market shocks, and evaluations of network-aware partner recommendations.
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Computer Vision
Texture Image Classification Using DWT AlexNet Feature Fusion and Deep Neural Networks
Arun D. Kulkarni
Texture image classification plays a significant role in computer
vision applications, including industrial inspection, medical image analysis, remote sensing, and object recognition. Handcrafted features can capture local texture characteristics but may have limited capability to represent complex visual patterns. In contrast, deep learning models automatically learn discriminative representations but may not fully exploit the multiscale spatial-frequency information inherent in texture images. This paper proposes a hybrid feature fusion framework, termed DWT_AlexNet_DNN, which combines Discrete Wavelet Transform (DWT) features with deep features extracted using AlexNet for texture image classification.
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Systems and Control · Cross-listed from quant-ph
Beyond sensitivity: mechanism-resolved error budgets for designing quantum sensors
Nima Leclerc, Marco Capelli, Kevin James Rietwyk et al. (+14 more)
Quantum sensors are specified by a headline sensitivity, yet applications also demand accuracy and reliability. The dominant limiter of one metric is often known, but no method resolves how interacting mechanisms combine into a signed, per-mechanism budget for each metric. We introduce a framework that computes a sensor's sensitivity, accuracy, and robustness from one open-system simulation and attributes each to its limiting mechanism. For a nitrogen-vacancy diamond ensemble the attribution inverts across metrics: dephasing limits sensitivity, the thermal ground-state shift limits accuracy, and optical leakage limits robustness. At identical sensitivity the recovered-field bias spans $8$ to $1500$\,nT, so tuning to sensitivity alone can miss the accuracy target by two orders of magnitude. The same modeling transfers to a cesium optically pumped magnetometer recording a human magnetocardiogram. As a digital twin, it predicts the gain from addressing each limiter, so sensors can be designed to the required metrics.
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All authors Nima Leclerc, Marco Capelli, Kevin James Rietwyk, Mark Dong, Dmitry Lyakh, Geoffrey Iwata, Brandon Rodenburg, Sean Oliver, Benedikt Kloss, Jin-Sung Kim, Stefan Bogdanovic, Yunheng Chen, Meysam Sharifzadeh Mirshekarloo, Cedric Weber, Marcus Doherty, Ethan Pratt, Joseph Hagmann