Signal Processing · Cross-listed from cs.IT
Compressibility is not Feedback: A Random-access Gap in Causal Semantic Repair
Milad Bafarassat
Semantic feedback can repair a noisy first decode without retransmitting the whole message, but current end-to-end evaluations hide where a feedback design fails. An oracle that sees both the source-side state and receiver observation may describe a useful correction with few bits, while the receiver, which sees only its own observation, may not know which correction to request. We formulate these as distinct direct and receiver-constrained coding problems, connect repair distortion to retained local utility and prove a random-access separation: one direct bit is exact although receiver utility vanishes with the number of source-conditioned alternatives. A synthetic ladder verifies the exact law. In paired populations of eight Reuters text-JSCC codecs, the trained recurrent population retains over three times more direct 16-bit repair value than the trained DeepSC population despite comparable full-repair opportunity. Nevertheless, an
entropy-valid receiver audit across all eight recurrent checkpoints does not resolve against repetition, source-only or shuffled-index controls. The results show that compressible repair is an upper bound, not evidence of deployable feedback, and motivate reporting both rate curves under matched resources.
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Signal Processing
One-Bin Fourier Challenges for Dimension-Free Reconstruction Certification
Milad Bafarassat
Partial-
Fourier measurement underlies computational imaging, and its reconstructions increasingly come from iterative or learned solvers whose recovery guarantees are conditional on a signal model, a sampling law, and solver accuracy. None of those guarantees transfers to a particular committed output: it can satisfy every acquired coefficient while remaining badly wrong in the unmeasured nullspace. Native
Fourier holdout does not repair this, since a spectrally concentrated error is missed unless its bin is drawn, so uniform worst-case risk needs a number of hidden bins proportional to the dimension. We propose a post-commit acceptance test: secret finite-phase masks turn one fixed
Fourier readout into dense randomized residual checks, and a median-of-means threshold handles calibrated readout noise. We prove that errors above $E_{\rm rej}$ are rejected and errors below $E_{\rm acc}$ are accepted with confidence $1-\delta$ once $q\ge C(1+N\sigma^2/E_{\rm rej})^2\log(1/\delta)$, explicitly exposing the one-bin resolution floor $N\sigma^2/\sqrt q$; in the zero-noise limit, QPSK gives $4^{-q}$ soundness versus $97.9\%$ minimax false acceptance for a worst-case ordinary-bin error. At a fixed noise-to-threshold ratio, measured screening false acceptance fell from about $21\%$ at 16 checks to $5\%$ at 64; a data-consistent learned nullspace failure with NMSE $0.200$ was rejected by $96.9\%$ of challenge banks while 16 ordinary bins missed it $98.9\%$ of the time; and error statistics at 16 checks stayed stable from 128 through $65{,}536$ dimensions. The test supports solver acceptance, model selection, and stopping certification, with a certified fresh-bank error interval.
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Systems and Control · Cross-listed from cs.AR
Spectral Signatures for Parametric Fault Detection in Flexible Electronics
Paula Carolina Lozano Duarte, Sule Ozev and Mehdi Tahoori
Flexible electronics (FE) based on indium gallium zinc oxide (IGZO) unipolar thin-film transistor (TFT) technologies enable lightweight, conformable systems for wearable sensing, biomedical monitoring, and human-machine interfaces. These applications rely on analog and mixed-signal (AMS) blocks that must remain accurate despite key challenges: increased device variability from low-cost unipolar fabrication; susceptibility to post-manufacturing failures due to the absence of rigid packaging; parametric faults that degrade analog accuracy without hard digital failures; and the high cost and in-field inaccessibility of specialized Automatic Test Equipment (ATE) for disposable FE systems. Conventional test approaches relying on analog-to-digital converters (ADCs) incur prohibitive area overhead in resource-constrained systems; critically, ADC accuracy is itself subject to process, voltage, and temperature (PVT) variations, leading to test invalidations. This work proposes a frequency-domain test signature
circuit exploiting spectral energy from a voltage-controlled oscillator (VCO) to detect faults and parametric deviations in AMS
circuits under test. The VCO converts fault-induced control-voltage deviations into frequency shifts processed through lightweight analog filters. RMS values of harmonic components serve as compact signatures with monotonic sensitivity to operating-point deviations while preserving ordering across PVT corners, ensuring robust operation without precision references or matched comparators. A ratiometric refinement suppresses post-calibration drift from temperature and supply variation by up to an order of magnitude. The signature is readable via two I/O pins, enabling in-field test without ATE. The
circuit occupies 6390 $\mu$m$^2$ and consumes 16.7 $\mu$W, achieving 26$\times$ area reduction versus compact ADCs and nearly 1500$\times$ versus SAR implementations.
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Signal Processing
A Low-Cost IoT Device for Environmental Monitoring and Embedded Solar Forecasting with On-Device Incremental Learning
Erick Michel Lara Pinal, Abhinav Das and Stephan Schlüter
Hyperlocal meteorological sensing is essential for accurate solar photovoltaic forecasting, yet professional-grade meteorological stations require investments easily exceeding 1000~USD per node, making distributed deployments economically inaccessible. This work presents a modular internet of things (IoT) device based on the ESP32 microcontroller integrating temperature, humidity, luminosity, and solar irradiance sensors in an IP68-rated enclosure at a total hardware costs of about \$65~USD when components are sourced in Germany. A hybrid architecture decouples external model training, performed on a conventional computer using the software Python and the open-source library TensorFlow, from autonomous 24-hour solar voltage forecasting executed on-device via a three-layer feedforward network with 3{,}011 parameters (11.8\,KB). The network is trained offline on site-collected data and deployed on the microcontroller as static weight matrices without cloud connectivity. An on-device incremental gradient descent mechanism enables continuous model adaptation after deployment without external retraining. The system was evaluated through two field deployments: a short period of hardware and firmware validation in Ulm, Germany, and a 115-day deployment in Zapopan, Mexico, comprising 84~days of training and 31~days of autonomous operation with zero missing records. Over a clean 28-day daytime window, the embedded model attained a coefficient of determination of 0.9165 and a mean absolute error of 0.2975~V (4.65\% of the operational range), outperforming a climatology baseline (skill score 0.64) while not surpassing a 24-hour persistence baseline. A frozen-weight ablation confirms that the on-device update mechanism yields a small but statistically robust accuracy gain ($p = 0.001$), demonstrating that autonomous incremental learning is feasible on low-cost hardware without cloud connectivity.
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Signal Processing · Cross-listed from cs.AI
A Comprehensive Survey of Wireless Foundation Models for AI-Native 6G Networks
Naveed Khan, Besan Al Sbeihi, Maryam Alshehhi et al. (+1 more)
Foundation models are emerging as a transformative paradigm for AI-native sixth-generation (6G) wireless networks by enabling scalable, transferable, and data-efficient intelligence across diverse communication tasks. Unlike conventional deep learning models that are trained for individual applications, wireless foundation models (WFMs) learn generalized representations from large-scale heterogeneous wireless data and can be efficiently adapted to communication, sensing, localization, and network optimization tasks with minimal task-specific supervision. Despite rapid progress, current research remains fragmented across architectures, training paradigms, and application domains, with no unified survey dedicated to the design, learning, and deployment of WFMs. This survey presents a comprehensive and unified review of wireless foundation models. We first establish the fundamental concepts of WFMs and introduce a taxonomy that organizes the field according to model architectures, pre-training paradigms, and applications. We then review representative architectures, self-supervised pre-training strategies, parameter-efficient adaptation methods,
datasets,
benchmarks, and evaluation methodologies, highlighting their roles in enabling transferable wireless intelligence. Furthermore, we examine emerging applications spanning physical-layer signal processing, network intelligence, and cross-layer optimization, and discuss the key challenges of data availability, generalization, interpretability, efficient edge deployment, and standardization. Finally, we outline future research directions toward scalable, trustworthy, and general-purpose wireless intelligence for AI-native 6G networks. This survey provides a comprehensive reference for researchers and practitioners developing next-generation intelligent wireless systems.
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All authors Naveed Khan, Besan Al Sbeihi, Maryam Alshehhi, Nasir Saeed
Systems and Control · Cross-listed from cs.RO
Protection Levels for Vision-Based Pose Estimation
Olivia Beyer Bruvik, Romeo Valentin, Marc R. Schlichting et al. (+2 more)
Vision-based navigation complements Global Navigation Satellite Systems, but certification demands integrity guarantees that account for faulty measurements. Previous work presented a probabilistic computer
vision pipeline for runway-based pose estimation with fault detection inspired by Receiver Autonomous Integrity Monitoring. This work extends that framework by deriving protection levels, which provide probabilistic bounds on pose error that remain valid under undetected faults. We present an
algorithm for computing protection levels for the nonlinear Perspective-$n$-Point problem applied to an aviation setting. The
algorithm covers all six degrees of freedom of the aircraft pose (position and orientation) directly. We analyze the effect of measurement redundancy, pixel-level prediction uncertainty, and runway distance on the resulting protection levels. To make the results tangible, we demonstrate tradeoffs in the protection levels on an illustrative runway example.
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All authors Olivia Beyer Bruvik, Romeo Valentin, Marc R. Schlichting, Don Walker, Mykel J. Kochenderfer
Image and Video Processing
MD2G-Cast: Relay-Coordinated Multicast for Scalable Volumetric Streaming over MoQ
Ruonan Chai, Yisu Wang, Zili Meng et al. (+1 more)
Volumetric streaming remains difficult to scale because receivers with overlapping fields of view are often served independently, causing repeated transmission of shared content. We present MD2G-Cast, a relay-coordinated multicast framework over Media over QUIC with an application-aware control layer for scalable multi-user volumetric delivery. MD2G-Cast jointly uses viewing overlap, receiver capability, and bandwidth conditions to form reusable multicast groups, share common Base content, and selectively admit Enhanced delivery. We formulate grouping and Enhanced admission as a sequential control problem, realize it with Proximal Policy Optimization (PPO), and train a compact relay model with teacher guidance for Enhanced admission. We implement MD2G-Cast with real MoQ processes and evaluate it with real access and 6DoF viewing traces for up to 100 users. At 20 and 100 users, MD2G-Cast keeps the receiver-side $P_{99}$ delivery interval below 40 ms across all seven access profiles, while Rolling reaches the 500 ms reporting cap in most cases. Across the evaluated user scales, MD2G-Cast achieves the highest or tied-highest mean system utility under homogeneous access and the highest mean utility under heterogeneous access, while reducing aggregate link load by about 27% relative to Clustering at 100 users. A matched relay-control ablation separates the control structure from its optimizer, showing that random feasible actions reduce utility while deterministic control remains competitive with PPO. Together, the results support relay coordination and selective Enhanced admission, rather than a particular policy optimizer, as the central design contribution.
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All authors Ruonan Chai, Yisu Wang, Zili Meng, Dirk Kutscher
Systems and Control
System Identification and acados-Based NMPC for Swing-Up Control of an Underactuated Double Pendulum
Sichen Li, Venkateswarlu Reddy Konkala, Xiaojie Ning et al. (+1 more)
We identify a base-parameter model of CloudPendulum
cell 203 and track an offline swing-up reference with acados SQP-RTI NMPC at a target rate of 400 Hz. A 5 mNm passive-joint assist enabled development-stage swing-up and recovery. In organizer-run testing (16 trials of 300 s per configuration on
cells 201–204), assisted pendubot and acrobot mean uptime scores were 80.19 s and 74.61 s. Acrobot scored zero on two
cells, and seven trials ended on safety-limit exceptions. Because the assist is prohibited in evaluation, these results are diagnostic rather than qualification scores.
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All authors Sichen Li, Venkateswarlu Reddy Konkala, Xiaojie Ning, Abhishek Alaya Udupa
Systems and Control · Cross-listed from cs.RO
From Operational Design Domain to Action: A Systematic Behavioral Taxonomy for Autonomous Driving
Chaitanya Shinde, Hadi Hajieghrary and Miguel Hurtado
Operational Design Domain (ODD) specifications describe where an automated driving system (ADS) is permitted to operate, but they do not prescribe what the ADS must demonstrably do once deployed within that domain. This gap between operating condition specification and behavioral validation represents a critical unresolved challenge in ADS safety assurance. This paper presents a structured, standards-grounded taxonomy of 21 behavioral competencies organized across three operational domains-Highway (HWY), Urban (URB), and Hub (HUB)-derived systematically from the PEGASUS six-layer model-based ODD. Each behavior is decomposed along longitudinal and lateral control axes and characterized against a four-property framework: Safety (gap maintenance, conflict avoidance, kinematic stability), Compliance (legal rules and behavioral norms), Comfort (rider dynamics and trust), and Efficiency (mission completion and product-level metrics). We further demonstrate that the crossing of ODD layer parameterizations with behavioral competency specifications yields concrete scenario families suitable for systematic behavioral testing and SOTIF coverage evidence. The taxonomy is grounded in AVSC00008202111, SAE J3237, and SAE J3016, and is validated as an operational specification layer through its deployment in a rule-enforced trajectory optimization system. The Hub domain is identified as a structurally distinct, underspecified domain warranting dedicated research
attention.
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Systems and Control
Two-stage monitoring design and budgeted condition-based maintenance for LED lighting systems: a gamma-process-based ensemble Kalman filter approach
Haohao Shi, Huy Truong-Ba, Michael E. Cholette et al. (+3 more)
Light-emitting diode (LED) luminaires degrade gradually during operation, reducing working plane (WP) illuminance and increasing the risk of inadequate indoor lighting. Because individual luminaire degradation states are difficult to measure directly after installation, this paper estimates latent luminaire degradation states from sparse in situ WP illuminance measurements. A two-stage monitoring design and budgeted condition-based maintenance (CBM) optimization framework is proposed. At the design stage, Radiance simulations are used to construct a linear-Gaussian observation model that maps latent luminaire degradation states to WP illuminance measurements. An identifiability-constrained D-optimal design then selects an informative reference layout of WP measurement points for inverse state estimation at a single epoch. At the runtime stage, the measurement design determines the visit schedule and the active reference measurement points for each visit, while an ensemble Kalman filter (EnKF) combines these sparse measurements with nonhomogeneous gamma process degradation predictions to update latent luminaire degradation state estimates. Posterior predictive failure probabilities are used as the risk metric for preventive replacement. Under a monitoring budget, the resulting runtime monitoring and CBM policy jointly selects the visit schedule, active reference measurement points, and risk threshold to minimize expected total downtime and replacement cost. A case study on an office lighting zone demonstrates design-stage measurement layout selection, runtime-stage measurement design, and budgeted CBM policy optimization.
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All authors Haohao Shi, Huy Truong-Ba, Michael E. Cholette, Brenden Harris, Juan Montes, Tommy H.T. Chan
Systems and Control
Horizon-Dependent Tube MPC for Spacecraft Rendezvous on Elliptical Orbits with Conditional Robust Constraint Satisfaction
Omer Burak Iskender
Spacecraft rendezvous on elliptical orbits must hold a safety corridor under navigation noise, unmodelled perturbations, and thrust errors driven by propellant mass uncertainty. This paper develops a tube-based model predictive controller for the Yamanaka-Ankersen linear time-varying dynamics, carrying constraint-tightening tube methods from circular to elliptical orbits. A horizon-dependent, element-wise error bound propagates the actual closed-loop
matrices along the prediction window, so early prediction steps keep nearly the full corridor that a constant-width tube would surrender. A multiplicative-to-additive conversion folds mass and thrust uncertainty into the same tightening recursion, and a Perron-Frobenius spectral-radius condition supplies a computable certificate that the tightening converges, with an explicit input-to-state stability gain. In a paired Monte Carlo campaign on a Mars sample-return orbit, the tube controller cuts mean corridor violations by more than an order of magnitude against a nominal predictive baseline at comparable fuel cost. A nonlinear truth-model test with oblateness perturbations well beyond the assumed disturbance budget leaves the corridor unviolated, and when the design envelope is exceeded the tightened problem becomes infeasible and the controller reverts to a saturated linear fallback, making the loss of guarantee explicit rather than silent. The construction requires only element-wise arithmetic and an open-source quadratic-programming solver.
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Signal Processing
Latent Semantic State Estimation for Reliable Swarming of UAVs under Intermittent Connectivity
Paris A. Karakasis and Walid Saad
Cooperative multi-unmanned aerial vehicle (
UAV) reconnaissance is often hindered by intermittent air-to-air communications where link dropouts lead to uncoordinated exploration and redundant mapping. Existing approaches rely on explicit exchange of high-dimensional spatial data or raw observations, incurring significant overhead, and often revert to reactive individual exploration during outages. This paper proposes a
memory-augmented framework in which each
UAV maintains a structured latent state decomposed into map, task, and
memory components. During dropout, a generative predictor conditioned on the
memory state infers substitute peer messages in the latent space, making the estimation task more tractable and directly aligned with the cooperative objective. The framework is trained end-to-end under the centralized training with decentralized execution paradigm. Simulation results demonstrate that the proposed framework closely matches the performance of a fully connected swarm, while remaining robust across a wide range of link failure conditions.
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Systems and Control · Cross-listed from cs.RO
Hierarchical Topology-Aware Planning and Control of Underwater Vehicle-Manipulator Systems in Confined Environments
Mohamed Abdelwahab, Ruggero Carli, Damiano Varagnolo et al. (+1 more)
This paper addresses autonomous intervention with an underwater vehicle–manipulator system (UVMS) in confined, cluttered, and partially known environments, where poor maneuverability, narrow passages, and uncertain execution may cause the
robot to enter unrecoverable regions. We propose MANTA, a three-layer hierarchical planning-and-control framework that couples passage accessibility, manipulation feasibility, and closed-loop execution. The first layer performs global connectivity
reasoning in a conservative reduced base space to extract traversable corridor candidates toward the task region. The second layer refines each candidate corridor by jointly optimizing the continuous base motion and arm trajectory, producing a collision-free base–arm trajectory. The third layer learns a reach-and-hold base policy using Gaussian-process model-based reinforcement learning (MBRL) through MC-PILCO, enabling trajectory tracking and station keeping at the planned manipulation state. During execution, the framework monitors map updates and can trigger recovery and route repair when the active passage becomes infeasible. MANTA is evaluated in confined UVMS planning and closed-loop tracking experiments. Across 120 matched planning queries, it achieves higher task success than full-state sampling-based baselines while producing larger clearance margins and lower arm motion. The learned MC-PILCO policy further reduces position and yaw tracking errors on both training and unseen tube-like references. These results show MANTA as a structured and data-efficient framework for safe autonomous underwater intervention in caves, tubes, and cluttered subsea structures.
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All authors Mohamed Abdelwahab, Ruggero Carli, Damiano Varagnolo, Alberto Dalla Libera
Systems and Control
Preview-Based Relative-Motion Control of an Insertion Tool for Neural-Thread Placement in Pulsating Tissue
Yongyan Cao and Xiaobo Li
Flexible neural electrode threads must be placed at a prescribed depth while the cortical surface moves with cardiac and respiratory pulsation. A controller tracking a fixed point in the laboratory frame cannot distinguish commanded insertion from tissue motion; the error appears as both a depth offset and relative tip–tissue velocity during contact. This paper formulates thread insertion in tissue-relative coordinates: a harmonic observer predicts delayed cortical-surface motion over the control horizon, a constrained MPC regulates the tip relative to that prediction while limiting actuator effort and lateral relative velocity, and an augmented disturbance state removes the steady offset from persistent contact force and model mismatch. In a 1-DOF MuJoCo
benchmark, the controller reaches RMS relative-placement errors of 12.0\um\ free-space and 1.9\um\ in contact, versus 18.3/176.8\um\ for delayed-feedback impedance and 286.1/275.5\um\ for laboratory-frame PD – the lower contact offset costs more peak contact force (3.43 vs.\ 2.00~mN), since it drives to commanded depth rather than yielding to tissue. A 3-DOF extension reduces lateral shear velocity from 1.34 to 0.50~mm/s at 2.1\um\ lateral placement error, and a feasibility-restoring soft-slack formulation keeps the shear constraint solvable under degraded sensing where a matched hard-constraint controller fails. A two-vertex Lyapunov certificate for the finite-horizon gain holds over $-40\%/{+}50\%$ reflected-mass mismatch, and the 1-DOF QP solves in under 0.4~ms at the 95th percentile. These results are a simulation-based control
benchmark, not a clinical safety claim: the modeled tip is a rigid contact point, and flexible-thread mechanics, a validated force constraint, biological damage thresholds, and hardware-realistic sensing and timing remain necessary before deployment.
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Systems and Control
Smooth globally PLI functions are nonlinear least-squares, and so are their gradient-dominated cousins
Eduardo D. Sontag
Boumal, Criscitiello and Rebjock (BCR) proved that if $M$ is a contractible, connected and complete Riemannian
manifold, then every smooth function $f\colon M\to R$ satisfying the global Polyak–Łojasiewicz inequality (PŁI) is necessarily of the form $f = f^* + \|\phi\|^2$ with $\phi$ a submersion. Informally, minimizing such a function amounts to solving a nonlinear least-squares problem in new coordinates. The global PŁI hypothesis fails, however, in many problems of interest, among them continuous-time LQR policy optimization in optimal control and a standard formulation of logistic regression. A hierarchy of weakened PŁ inequalities has been introduced in order to cover such problems, and more generally to study the effect of noise and
adversarial perturbations on gradient flows. This note shows that, with minor modifications, the same reduction to a nonlinear least-squares problem holds under a substantially weaker hypothesis, “semiglobal” PŁI, which is satisfied in both of the examples just mentioned. That condition asks that $f$ satisfy an estimate $\|\nabla f(x)\| \ge \alpha\bigl(f(x)-f^*\bigr)$ for all $x$, with $\alpha$ merely positive definite and bounded below by a positive multiple of $\sqrt{s}$ for small $s>0$.
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