Signal Processing
Movable-Element STAR-RIS for 6G Non-Terrestrial Networks: Architectures, Enabling Technologies, and Open Challenges
Wali Ullah Khan and Muhammad Adil
Non-terrestrial networks (NTNs) are emerging as a key component of 6G systems by extending ubiquitous and resilient connectivity across satellite, aerial, and terrestrial layers. However, severe propagation loss, rapidly varying geometry, Doppler, blockage, and stringent payload and energy constraints make efficient beam and propagation control particularly challenging. Movable-element
STAR-RIS (ME-
STAR-RIS) offers a new approach by combining full-space transmission/reflection control with reconfigurable surface geometry, thereby introducing an additional spatial degree of freedom for geometry-aware NTN operation. In this article, we first describe the operating principle, movement constraints, and potential hardware realizations of ME-
STAR-RIS, and then present representative satellite-borne, aerial-relay, and cross-tier NTN architectures. We discuss the key enabling mechanisms, including joint geometry–electromagnetic optimization, mobility-aware channel acquisition, multi-timescale control, and predictive configuration. A LEO-centered numerical case study compares ME-
STAR-RIS with an otherwise identical fixed
STAR-RIS and demonstrates the benefit of element mobility across different transmit powers, movement ranges, and surface sizes, while revealing diminishing returns from increasingly large displacements. Finally, we discuss the main hardware, CSI, scalability, near-field, sensing, security, reliability, and standardization challenges, and highlight promising directions toward practical ME-
STAR-RIS-enabled NTNs
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Signal Processing
Utility-Aware Adaptive Downlink DM-RS Allocation from Uplink CSI for Lightweight O-DU dApps
Seungwon Min
Adaptive demodulation reference signal (DM-RS) placement in 5G New
Radio (NR) trades pilot overhead against channel-tracking robustness, making a single static density suboptimal across heterogeneous mobility and propagation regimes. This paper studies a lightweight per-UE controller intended for O-DU-side distributed application (dApp) execution. The controller consumes eleven deployable uplink-CSI statistics and selects among six standards-derived PDSCH DM-RS configurations. Rather than optimize oracle-class accuracy, we train an 11-128-64-32-6 multilayer perceptron with a utility-aware objective that preserves the throughput structure of all candidate actions. In a large-scale trajectory-disjoint evaluation covering 294 channel/speed/SNR conditions and 7,056 observations, the proposed U-SoftCE policy significantly improves throughput over a training-selected best fixed pattern by 1.30, 0.86, and 1.13 percentage points on in-distribution, CDL channel-OOD, and 300-km/h mobility-OOD splits, respectively; paired 95% bootstrap intervals exclude zero in all three cases. An independent bit-accurate Sionna NR LDPC validation over 36 held-out conditions and 50 transport blocks per candidate retains a +1.21-point gain with a 95% cluster-bootstrap interval of [0.27, 2.13]. A native C++ implementation uses 12,070 dense parameters and requires 5.59 microseconds mean inference time, while a FlexRIC-based emulated O-DU prototype demonstrates sub-10-ms closed-loop operation. These results support utility-aware objectives for compact adaptive PHY controllers while exposing the limits of exact class-accuracy optimization.
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Systems and Control · Cross-listed from cs.RO
Mission Performance: Automatic and Adaptive Race Pace Progression for Autonomous Racing
Giovanni Lambertini, Matteo Pini, Nicola Musiu et al. (+3 more)
In this paper, we describe the Mission Performance module implemented for a fully autonomous racing car to automatically manage the longitudinal, lateral, and combined performances, aiming to speedup the laptime progression while assuring safety. Motivated by the difficulty and risks of applying the real-time estimation of the grip to critical modules like the motion planner and controller, the Mission Performance guides these modules adapting their target performance instead of changing the vehicle model parameters. The module is formed by pre-defined progressions to warm up the tires at the beginning of a run. Then, the system continuously monitors safety and vehicle dynamics metrics on a per-sector basis to adaptively reduce, maintain, or increase the performance levels for each sector, progressively converging toward the maximum allowed value. The solution's effectiveness is demonstrated on the EAV-25, a fully autonomous Dallara Superformula, at the Yas Marina
Circuit during the Abu Dhabi Autonomous Racing League (A2RL) Season 2.
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All authors Giovanni Lambertini, Matteo Pini, Nicola Musiu, Ayoub Raji, Francesco Iacovacci, Marko Bertogna
Systems and Control · Cross-listed from cs.LG
Adaptive Chemotherapy Control under Tumor Heterogeneity via Reinforcement Learning
Bereket Sitotaw Kidane, Md Samiul Haque Motayed and Shuo Wang
Designing effective chemotherapy regimens is hindered by tumor heterogeneity and drug resistance, which complicate the deployment of patient-specific model-based optimal control across diverse populations. We develop and compare closed-loop deep reinforcement learning (DRL) dosing policies with continuous (TD3) and discrete (DQN) action spaces trained on a high-dimensional heterogeneous tumor model. The DRL policies are benchmarked against a Pontryagin's Maximum Principle (PMP)-derived open-loop
benchmark. We assess generalization under parametric heterogeneity using a 100-patient virtual cohort with plus or minus 10 percent uniform perturbations in growth and drug-sensitivity parameters. Across this cohort, TD3 achieves higher average tumor reduction, while DQN yields tighter inter-patient dosing consistency, revealing a clear efficacy-consistency trade-off in this study. Our simulations assume full observation of all tumor subpopulations; translation to sparse and noisy clinical measurements will require partial-observability formulations and/or state estimation. Overall, the results show that simulation-trained DRL can learn state-dependent feedback dosing policies that complement open-loop optimal control
benchmarks.
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Audio and Speech Processing · Cross-listed from cs.SD
DriftSE: Speech Enhancement with Generative Drifting
Liang Xu, Diego Caviedes-Nozal, W. Bastiaan Kleijn et al. (+2 more)
We propose DriftSE, a novel one-step generative framework for
speech enhancement formulated as a latent distribution
equilibrium problem. During training, the drifting field aligns the generator's pushforward distribution with the clean
speech manifold through drifting in a latent domain. During inference, the drifting process is discarded, enabling one-step generation. We establish that its enhancement quality depends fundamentally on the choice of latent representation. Semantic latents preserve phonetic structure but fail to capture physical acoustic cues, whereas acoustic latents reconstruct the physical signal but risk linguistic
hallucination. Therefore, we introduce dual-latent drifting, performing parallel drifting in both semantic and acoustic latents to simultaneously preserve phonetic intelligibility and acoustic fidelity. Additionally, we demonstrate that DriftSE enables fully unpaired training by aligning latent distributions rather than exact point-wise targets. Consequently, DriftSE facilitates cross-
dataset learning in the absence of paired noisy-clean samples. Moreover, DriftSE exhibits broad architectural flexibility across different generator backbones. Extensive evaluations on additive denoising and convolutive dereverberation demonstrate robust one-step enhancement across both offline and real-time causal settings. Notably, DriftSE achieves state-of-the-art word error rates across all four evaluated
datasets while strictly operating at 1 NFE. Code and audio examples are available online.
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All authors Liang Xu, Diego Caviedes-Nozal, W. Bastiaan Kleijn, Longfei Felix Yan, Rasmus Kongsgaard Olsson
Systems and Control
Abstract homogeneous chains: a Lyapunov framework for high-order sliding modes in multi-agent systems
Rodrigo Aldana-López
This work develops a Lyapunov framework for a broad class of arbitrary-order sliding-mode
algorithms in multi-
agent systems. We introduce abstract homogeneous chains, a class of nonlinear error systems characterized by common convexity and homogeneity properties. For this class, we establish global finite-time stability for arbitrary order, construct a homogeneous Lyapunov function, and derive a recursive optimization-based gain-proposal procedure. The framework addresses several gaps in existing dynamic average consensus and distributed differentiation results: it provides a recursive numerical optimization-based gain-proposal procedure for EDCHO at arbitrary order, extends REDCHO convergence from local to global, and provides arbitrary-order numerical gain-proposal rules for leader-follower distributed differentiation, previously available only at first order. It also provides a new arbitrary-order observer for multi-leader affine formation tracking with global finite-time convergence.
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Signal Processing · Cross-listed from cs.LG
CRFCAN: A Complex-Valued Cross-Domain Residual Network for Joint Channel and Phase Noise Estimation in Sub-THz OFDM Systems
Ruilin Wang and Xiaodai Dong
In sub-terahertz (sub-THz) communications, the coupling of ultra-wide bandwidth and severe phase noise (PN) impairments renders conventional joint channel and PN estimation highly complex and computationally prohibitive. To address this, we propose CRFCAN, a complex-valued residual FFT convolutional
attention network designed for joint channel and PN estimation. Unlike existing deep learning schemes that rely on cascaded networks or hybrid frameworks combining neural networks with conventional iterative
estimators, CRFCAN performs joint recovery in a truly end-to-end fashion through a physics-inspired cross-domain structure. Specifically, Fast
Fourier Transform (FFT) and inverse FFT modules are embedded within residual groups to enable iterative feature interaction across the time and frequency domains, thereby capturing both frequency-selective fading and time-varying phase distortions. In addition, two dedicated residual blocks are introduced for complex feature extraction and multiplicative phase-distortion modeling, respectively. A physics-aware PN output tail with soft normalization is further employed to improve estimation stability while preserving the physical characteristics of the effective PN process. Simulation results demonstrate that CRFCAN significantly outperforms conventional
algorithms and state-of-the-art deep learning models in terms of normalized mean square error (NMSE) and bit error rate (BER). Notably, CRFCAN achieves superior performance with single-shot, fixed-complexity inference and generalizes well to unseen PN models without fine-tuning, highlighting its robustness and practicality for sub-THz receivers.
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Signal Processing · Cross-listed from cs.HC
BRIDGE-EEG: Bridging Self-Supervised Pretraining and Efficient Deployment for Cross-Dataset EEG Classification
Meghna Roy Chowdhury, Chengwei Zhou, Haotian Yu et al. (+2 more)
The growing use of electroencephalography (
EEG) motivates automated analysis that is accurate, transferable, and deployable on constrained hardware. Recent
EEG foundation models learn general representations from large-scale pretraining, but their size and computational cost limit edge and wearable deployment. We introduce BRIDGE-
EEG, an efficient multi-task
EEG classification pipeline that preserves the benefits of pretraining while reducing model size. A unified preprocessing scheme maps heterogeneous recordings with different channel counts, montages, and sampling rates to a device-agnostic 62-channel time–frequency representation. We pretrain an SE-ResNet18 teacher (11.84 M parameters) with SimCLR on unlabeled
EEG from five heterogeneous
datasets, then compress it into SE-ResNet8 (1.56 M) and SE-ResNet4 (0.48 M) students using task-agnostic and task-specific
distillation. We evaluate six
benchmarks spanning abnormality detection, motor imagery, and emotion recognition. For abnormality detection and emotion recognition, the students achieve accuracy comparable to or better than several recent
EEG foundation models with 10–1,000$\times$ more parameters. Motor imagery shows a remaining representation gap, highlighting the importance of pretraining diversity. Inference profiling on a server GPU, desktop CPU, and NVIDIA Jetson Orin Nano shows up to 3.0$\times$ lower edge energy per inference (15.64 mJ vs. 46.67 mJ). The compact models further support future deployment on MCU-class wearables.
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All authors Meghna Roy Chowdhury, Chengwei Zhou, Haotian Yu, Gourav Datta, Shreyas Sen
Signal Processing
CORDIS: A Scalable Coordinated Resource Allocation Framework for Distributed Cell-Free ISAC
Mehdi Zafari, Björn Ottersten and A. Lee Swindlehurst
Integrated Sensing and Communication (
ISAC) is envisioned as a key technology for 6G wireless networks, enabling the joint use of spectrum and hardware for sensing and communication. In multi-static
cell-free architectures, coordinating beamforming and power resources across distributed access points (APs) is critical in order to mitigate severe communication-sensing interference. Most existing
ISAC resource allocation solutions rely on centralized architectures with full network knowledge, which limits their scalability and practicality in distributed
cell-free deployments with imperfect channel state information (CSI). In this paper, we introduce a framework for COordinated Resource allocation for Distributed
ISAC Systems (CORDIS) that optimizes network sensing while suppressing clutter and maintaining per-user communication performance constraints. Two
algorithms are developed: CORDIS-Split, a low-overhead scheme that pairs fixed local beamformers with centralized power allocation, and CORDIS-ADMM, which jointly optimizes beamforming and power through the consensus Alternating Direction Method of Multipliers (ADMM). By localizing high-dimensional
matrix operations, both
algorithms ensure fronthaul overhead and per-AP computation remain independent of
antenna and AP counts. Simulations demonstrate that CORDIS-ADMM approaches the centralized performance bound and degrades gracefully under CSI estimation error, remaining effective even with locally rank-deficient channels, while CORDIS-Split offers a minimal-overhead alternative. These results confirm that CORDIS is a scalable and communication-efficient foundation for robust
ISAC in decentralized wireless networks.
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Systems and Control · Cross-listed from cs.RO
Battery-Aware Predictive Trajectory Planning and Control for Multirotors Under Disturbances
Krishna Bhavithavya Kidambi
This paper presents a battery-aware predictive trajectory-planning and control framework for multirotors operating under spatially localized disturbances. Candidate trajectories are evaluated through closed-loop vehicle–motor–battery propagation, allowing disturbance-induced control demand, electrical energy, battery
evolution, and terminal-voltage-dependent actuator capability to enter the planning process. % A reduced-order battery model is numerically benchmarked against an independently implemented Simscape equivalent-
circuit reference, with a power NRMSE of $0.64\%$ and a cumulative-energy discrepancy below $0.7\%$. % In a $150$-s, $640$-m mission containing three disturbance regions, the selected trajectory reduces electrical energy consumption by $7.46\%$ and position-tracking RMSE by approximately $72\%$ relative to the disturbance-aware fixed-reference baseline. % Planner ablations show that battery-dependent terms are nonbinding at nominal SOC but alter the selected trajectory under a depleted-battery stress condition. % Execution with multiple feedback controllers further demonstrates that controller selection changes the tradeoff among tracking accuracy, energy consumption, and actuator utilization. % The results demonstrate the benefit of accounting for predicted closed-loop energetic and battery–actuator consequences during trajectory selection.
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Signal Processing · Cross-listed from cs.IT
Random Access and Localization in Cell-Free User-Centric Networks with Multipath Channels
Simon Tarboush, Eleni Gkiouzepi and Giuseppe Caire
In a wireless network, the initial/random access mechanism (RACH) allows idle/new users to join the network and (possibly) request allocated transmission resources for subsequent traffic. Building on our own previous work, for
cell-free user-centric networks, we consider location-dependent random access codebooks such that users in a certain geographic area (location) make use of the corresponding set of random access preambles (codewords). We expand our previous work in two ways: (1) we consider multipath channels with line-of-sight (LoS) propagation within a given radius; (2) we consider two different approaches. The first makes use of Zadoff-Chu (ZC) sequences and GLRT detection to cope with the unknown delay, and it is conceptually similar to the 3GPP 2-step RACH specification (here extended to the
cell-free case). The second builds on our previous work on multisource approximate message passing (AMP). For both schemes, we also consider a novel near Maximum-Likelihood approach for localization of the random access users directly from the detected RACH preambles, implicitly using angle of arrival and time difference of arrival information embedded into the LoS components. Simulation results show that the AMP approach achieves generally better performance for random access user detection, while both approaches have similar localization capability with a slight superiority for the frequency-domain scheme.
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Signal Processing · Cross-listed from cs.IT
Joint Random Access and Localization in Cell-Free User-Centric Networks with Frequency-Selective Fading Channels
Simon Tarboush, Eleni Gkiouzepi and Giuseppe Caire
We study random access (RACH) schemes for
cell-free (CF) user-centric networks to handle many geographically distributed users with sporadic traffic and intermittent activity. The RACH must allow the system to: 1) detect preambles sent by the (yet unknown) random access users in the RACH slot; 2) localize them for fast allocation of user-centric
radio-unit (RU) clusters. Most prior work uses simplified models, neglecting frame-synchronous but chip-asynchronous transmission, possible line-of-sight (LoS) propagation for certain user-RU pairs, and multipath non-line-of-sight (NLoS) propagation yielding frequency-selective channels. Building on our previous work, we consider location-dependent partitioned random access codebooks where users in a geographic area (location) use the corresponding subset of random access preambles. We present a unified framework for joint detection and localization over a spatially consistent network-wide channel model, incorporating these neglected aspects. We evaluate two schemes: 1) a “legacy” scheme using Zadoff-Chu (ZC) sequences, extending the 3GPP 2-step RACH to the CF case; 2) our multisource approximate message passing (AMP) approach extended to multipath frequency-selective fading. For both schemes, we develop novel approximated GLRT preamble detection and Maximum-Likelihood position
estimators with super-resolution refinement, implicitly exploiting received signal strength, angle of arrival, and time-difference of arrival information embedded into LoS components. Numerical results show that the AMP-based scheme achieves superior preamble detection, while both schemes have similar and excellent localization capability.
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Systems and Control · Cross-listed from cs.GT
Deriving the Pure Price of Anarchy for Networked Resource Allocation Games
Vartika Singh and Philip N. Brown
This work considers multi-
agent coordination with arbitrary information networks among the
agents using a game-theoretic approach. A system designer aims to assign local utility functions to the
agents to guide their actions toward a desired system objective. The performance of the assigned local utilities is measured by the well known pure price of anarchy (pPoA) metric that equals the ratio of the system objective at the worst pure Nash
equilibrium of the corresponding game to the optimal system objective. Our aim is to derive the utility functions which optimize the pPoA-based performance guarantees for any given information network and system objective. We develop a linear program that derives the optimal pPoA for any arbitrary information network and arbitrary system objective. Our work is the first to solve optimal utility design for arbitrary networks; our techniques generalize previous approaches which considered only the full-information setting. For supermodular objective functions, we prove that counterintuitively, a fully communication-denied utility design is optimal irrespective of the original information network. For submodular system objectives, an exhaustive numerical analysis suggests that the optimal utility design is robust to communication failures even for this case. When the system objective is weighted maximum coverage, the marginal contribution utility design provably optimizes the pPoA for a wide variety of information networks of interest.
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Systems and Control · Cross-listed from cs.LG
Inverting Self-Triggered Control: Adversarial Reinforcement Learning for Sparse Denial-of-Service Attacks
Adam Haroon, Erick J. Rodríguez-Seda, Tristan Schuler et al. (+1 more)
Self-triggered reinforcement learning control (RL-STC) learns the sparsest control schedule that preserves Lyapunov-decreasing stability under a Run-Time Assurance (RTA) override. We invert this: an
adversarial RL
agent learns the sparsest jamming or Denial-of-Service (DoS) schedule that destabilizes the closed loop, with a Lyapunov-increase admissibility predicate mirroring the defender's safety certificate. We prove a plant-property lower bound on the minimum jam count required for an immediate hold-last medium-access-control adversary to force a crash against a self-triggered controller (STC) satisfying a Lyapunov contract, and recover a certificate-level analog of the consecutive-grouping optimality of prior count-budget DoS scheduling as a corollary. This extends the DoS-scheduling count-budget analysis from periodic and linear-time-invariant to STC controllers. Empirically, we train against four fixed defenders per plant (one Linear Quadratic Regulator (LQR) and three RL-STC) on Pendulum, CartPole, and Quadrotor2D. The learned adversary is the only adversary that crashes every defender on every plant at $100\%$: greedy misses Quadrotor2D LQR on $42\%$ of episodes and periodic misses Pendulum LQR on $97\%$. On jam-time-per-failure it beats baselines by up to $2.8\times$, and shows its widest absolute margin on Quadrotor2D LQR. Robustness ablations show that Gaussian observation noise exceeding the initial-state magnitude and position-only observation both preserve $100\%$ failure rate and keep the learned adversary strictly ahead of both baselines on jam-time-per-failure.
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All authors Adam Haroon, Erick J. Rodríguez-Seda, Tristan Schuler, Cody Fleming
Signal Processing · Cross-listed from cs.CV
3D Point Splatting for mmWave Radar Novel View Synthesis
Adnan Armouti, Yixuan Gao and Rajalakshmi Nandakumar
Solving novel view synthesis (NVS) for millimeter-wave (mmWave) radar requires a renderer that is physically faithful, complex-valued, and multi-viewpoint-tractable. No prior method achieves these three properties simultaneously. Differentiable Monte Carlo (MC) ray tracers implement the radar forward model directly with explicit material modeling and complex outputs, but do not scale to the multi-view optimization NVS demands. Optical-NVS ports of NeRF, hash grids, and 3D Gaussians train fast but discard phase and replace explicit material modeling with opaque learned features, restricting them to power-only range-azimuth (RA) magnitudes. We propose 3D Point Splatting (3DPS), the first differentiable point renderer for radar, derived directly from the standard solid-angle form of the radar equation. Each oriented 3D point carries an ITU-R P.2040 material model, evaluated in closed form, with the resulting complex phasor splatted into range bins through a precomputed point spread function (PSF). The complex-valued output makes the renderer product-agnostic. The same optimized scene yields analog-to-digital converter (ADC), complex range profile (CRP), and RA outputs through standard fast
Fourier transform (FFT) pipelines without retraining for each format. On six outdoor ColoRadar scenes, 3DPS reaches 0.587 mean Pearson correlation on held-out RA images. This is between 1.7x and 5.2x the three optical-NVS baselines (RadarSplat, Radar Fields, DART). Training takes approximately 3 minutes per scene on a single RTX 4090.
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Audio and Speech Processing
RetroThinker: Enabling Retrospective Thinking in Speech LLMs
Yi-Jen Shih, Puyuan Peng, Abdelrahman Mohamed et al. (+1 more)
Speech large
language models (SpeechLLMs) offer reduced latency and retain paralinguistic nuances that are typically lost in cascaded automatic
speech recognition (ASR) and text-based LM architectures. However, they continue to lag behind text-only LLMs on complex
reasoning tasks, while real-time spoken interaction imposes strict latency constraints. Although prior works employ Chain-of-Thought (CoT) and concurrent
reasoning to enhance
reasoning capabilities without inducing prohibitive delays, an inherent accuracy-latency trade-off persists. In this paper, we investigate whether a streaming SpeechLLM can dynamically revise its
reasoning traces on the fly. We introduce RetroThinker, a multi-stage post-training framework that equips the Moshi model to self-verify and forward-correct CoT steps during inference. RetroThinker combines supervised fine-tuning (SFT) on curated retrospective thinking data with length-based direct preference optimization (DPO) to optimize retrospective during early
reasoning (i.e.,
reasoning concurrently while the user speaks). Evaluated on the GSM8K
benchmark, RetroThinker significantly improves the accuracy-latency trade-off over non-retrospective baselines, achieving an 11% absolute accuracy gain at a comparable latency.
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All authors Yi-Jen Shih, Puyuan Peng, Abdelrahman Mohamed, David Harwath
Systems and Control · Cross-listed from cs.GT
Truncated Noisy Best-Response Algorithms: Toward Game Theoretic Learning with Safety Guarantees
Vartika Singh and Philip N. Brown
We consider a game theoretic approach to solve multi-
agent coordination problems with submodular maximization objectives. It is known for such problems that the Nash
equilibria for the corresponding game are always within 50% of the optimal, but that the
equilibria which achieve this worst-case bound are not stable. To exploit this instability, we propose a family of
algorithms which we call Truncated Noisy Best-Response (TNBR)
Algorithms. These
algorithms are flexibly characterized by
agents asynchronously and stochastically selecting actions from a neighbourhood of their best response payoffs. We compute bounds on the recurrent classes of TNBR
algorithms' associated Markov chains. Our bounds fall into two categories: first, "Performance" bounds ensure that TNBR
algorithms always have a high-value recurrent state; second, "Safety" bounds ensure that TNBR
algorithms never have arbitrarily-bad recurrent states. Furthermore, these two types of bounds are linked by a waterbed-like effect: every game with a poor Safety guarantee necessarily has a favorable Performance guarantee.
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Signal Processing · Cross-listed from cs.NI
From Open RAN to Open Spectrum: A Programmable, Intelligent Architecture for Multi-Service Spectrum Coexistence
Michele Polese, Minh Dat Nguyen, Paolo Testolina et al. (+1 more)
Considering sharing or coexistence from the perspective of spectrum alone fails to recognize that any spectrum-enabled service also requires (i)
radio and processing infrastructure and (ii) a protocol stack, including waveforms and signal processing pipelines. The efficiency of spectrum coexistence frameworks such as Citizen Broadband
Radio Service (CBRS) is thus limited to optimizing resource allocation across a single dimension. How to address this limitation, however, remains an open challenge, especially considering the diversity of requirements and operational modes across spectrum services (e.g., sensing, communications, navigation, or positioning). This article introduces Open Spectrum, an architecture that brings softwarization, programmability, and open interfaces to heterogeneous spectrum services, extending the open
Radio Access Network (RAN) principles beyond wireless networking. We propose to combine spectrum, services, and infrastructure in a common pool. Its resources are shared and orchestrated by a Spectrum Intelligent Controller (SIC), with plug-and-play spectrum applications, i.e., Spectrum Applications (sApps), and data-driven
Radio-Frequency Interference (RFI) modeling using Digital Twins (DTs). We describe the Open Spectrum architecture, shared infrastructure pool, and operational workflows for tenant onboarding and incentives, conflict resolution, and service sharing across sensing, radionavigation, radiolocation, and cellular systems. System-level simulations using the BostonTwin urban DT and Sionna ray tracing show that there exist performance-driven incentives in sharing infrastructure and sharing across multiple services, enabling increased access to spectrum and improvement in median Signal to Interference plus Noise Ratio (SINR) of up to 12 dB.
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All authors Michele Polese, Minh Dat Nguyen, Paolo Testolina, Tommaso Melodia
Systems and Control
Acoustic-based Guidance for Automatic Docking of Holonomic AUVs
Ravi Regalo, David Cabecinhas and António Pascoal
This paper describes a system to automatically dock an AUV onto a docking station without precise knowledge of the position and orientation of the latter, in the presence of unknown ocean currents, using a fully acoustic sensing architecture. The system relies on a pair of Ultrashort Baseline sensors, one onboard the vehicle and one installed on a seabed-resident docking station, enabling operation in low-visibility environments where cameras are ineffective. Relative orientation is estimated by a nonlinear complementary filter on $SO(3)$, while an Extended Kalman Filter provides relative position, supplying pose estimates to a
geometric controller on $SE(3)$ that executes the docking manoeuvre. The complete system is implemented in a dedicated software suite and validated in simulation and water trials.
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Systems and Control
Predefined-Time Resilient Integral Reinforcement Learning for Input-Constrained Unknown Nonlinear Systems Under FDI Attacks and Disturbances: A Fully Data-Driven Approach
Tien Dat Vu and Minh Doan
This paper investigates optimal control for nonlinear systems with unknown dynamics, input constraints, disturbances, and
adversarial signals. The objective is to develop a learning-based control method that allows the designer to prescribe the desired convergence time in advance. An integral reinforcement-learning framework is proposed to avoid requiring exact knowledge of the system dynamics while ensuring that the control input always satisfies the actuator constraints. Current and recorded data are combined to train the critic without requiring persistent excitation. The learning gain is selected directly from the prescribed convergence deadline. Lyapunov analysis is then used to establish practical predefined-time convergence of the coupled state-critic system in the presence of disturbances and
adversarial channels. The effectiveness of the proposed method is validated through the stabilization control of a two-link
robot manipulator.
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Systems and Control
Predefined-Time Leaderless Consensus Under Denial-of-Service Attacks
Lohitvel Gopikannan, Shashi Ranjan Kumar and Abhinav Sinha
This paper addresses predefined-time resilient consensus of leaderless second-order nonlinear multi-
agent systems under denial-of-service (DoS) attacks, motivated by coordination requirements in safety-critical applications. The
agents are subject to bounded external disturbances and communicate over a strongly connected directed graph whose links are simultaneously disabled during attacks. We develop a switching sliding-mode protocol with the objective of reaching an invariant
manifold of position and velocity agreement. The protocol uses relative position and velocity information during attack-free intervals and local velocity feedback during communication blackouts. A time-scaling function remains constant during each blackout and resumes evolving when communication is restored, accounting for the time available for consensus. Under bounds on attack duration and frequency, we derive sufficient gain conditions through a Lyapunov analysis. We show that, despite bounded disturbances, the
agents achieve position and velocity consensus by a realistic settling time equal to a prescribed convergence duration plus the cumulative attack duration up to the realistic settling time. The prescribed convergence duration is independent of the initial conditions, and the realistic settling time reduces to that duration in the absence of attacks.
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Signal Processing · Cross-listed from cs.CR
Differentially Private EEG Feature Anonymization: A Privacy-Utility Case Study in Clinical Neurophysiology
Noman Sadiq and Mohsen Toorani
Clinical electroencephalography (
EEG) data are valuable for healthcare research and for developing artificial intelligence (AI)-based clinical decision-support systems, but
EEG recordings and derived features may contain sensitive patient-specific information. This creates
privacy risks when data are reused, analyzed, or shared across clinical and research environments. Conventional anonymization methods are often insufficient for high-dimensional biomedical signals, since removing direct identifiers does not necessarily prevent re-identification, linkage, or inference risks. At the same time, strong
privacy protection may distort clinically relevant signal characteristics and reduce data utility. This paper studies subject-level differential
privacy for protecting clinical
EEG-derived feature representations using Gaussian and Laplace perturbations. The proposed framework considers three deployment scenarios: client-side anonymization, centralized server-side anonymization, and decentralized local training. Following
EEG preprocessing and feature extraction, Gaussian and Laplace perturbations are applied to the resulting patient-level
EEG feature representations. The Laplace experiments evaluate the implemented noise scales, while the scales required for formal full-vector calibration are derived separately. The effects of both perturbations are assessed using statistical utility measures and a downstream machine-learning-based utility check. The results show that differentially private perturbation can be integrated into
EEG processing workflows, but the selected mechanism,
privacy parameters, and sensitivity calibration strongly influence data utility. The study highlights the practical
privacy-utility trade-off in DP-based
EEG feature anonymization and the challenges of preserving downstream utility in small and imbalanced clinical
EEG datasets.
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Audio and Speech Processing
Whisper-Based Speech Transcription from Videos Across Multiple Languages for Cross-Cultural Understanding
Michael Picheny
Cross-cultural understanding has become increasingly important in today's highly connected, cross-national world. The success of LLM-based technologies is now driving the development of automated tools to aid understanding for nonnative people trying to succeed in cross-cultural environments. Building such automated tools is often done by leveraging in-thewild text, audio, and
video data. This paper presents techniques for improving
speech recognition-based transcript creation in multiple
languages from
videos to better train these automated tools. The focus is on processes and
speech tools that can easily be used by cross-cultural tool builders without requiring deep
speech processing expertise. Using publicly available
videos from YouTube and Whisper-based tools, average transcription error rate across seven
languages (Spanish, Japanese, Korean, Mandarin, Turkish, Russian, and Hebrew) of 30% are observed. With a modest amount of fine-tuning data, the average error rate can be reduced to 20% making such output much more usable for downstream processing.
Speech and metadata associated with these
videos that can be used by the community to further refine these experiments are released as well.
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Audio and Speech Processing
Not All Attacks Are Learned Equally in Speech Deepfake Detection
Avantika Singh, Aurosweta Mahapatra, Ismail Rasim Ulgen et al. (+3 more)
Speech deepfake detection (SDD) models are trained on multi-attack
datasets containing diverse spoofing systems, such as text-to-
speech (TTS) and voice conversion (VC). In standard classifier training on multi-attack
datasets, all attacks are treated as one spoofed class, and performance is reported using overall Equal Error Rate (EER). This aggregate view obscures how individual attacks shape learning and generalization. To better understand this attack-level behavior, we first balance TTS and VC exposure using sample and attack omission. We then measure attack-wise EER at inference and analyze attack-wise training loss and predictive
entropy to characterize optimization. Results show that attacks contribute unequally: some attacks have high EER sensitivity and concentrated
entropy with low loss, indicating strong influence on the decision boundary. We define these as high-impact attacks. To reduce uneven generalization across attacks, we propose a replay-regularized, attack-aware curriculum that steps exposure based on measured attack influence. Experiments on ASVspoof 2019, 2021, ASVspoof 5, and Fake-or-Real show improved overall robustness and reduced attack-level imbalance compared with standard multi-attack training.
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All authors Avantika Singh, Aurosweta Mahapatra, Ismail Rasim Ulgen, Nicholas Andrews, Kong Aik Lee, Berrak Sisman
Systems and Control
Construction of Control Lyapunov-Barrier Functions from CLF-CBF Pairs
Bo Wang and Miroslav Krstic
This paper studies the construction of control Lyapunov-barrier functions (CLBFs) from a given control Lyapunov function (CLF) $V$ and control barrier function (CBF) $h$. We consider functions of the form $W=F(V,h)$ that increase with the CLF value and do not increase with the barrier value, and show that the CLBF decrease condition is completely characterized by a nonnegative scalar weight that governs the relative contributions of the CLF and CBF. Because this weight depends only on $(V,h)$, the same value must satisfy the decrease condition at all states sharing the same CLF and CBF values, which leads to a joint-level-set admissibility condition. We then construct CLBFs from admissible weights through a first-order partial differential equation (PDE) and obtain explicit multiplicative and power-type families as special cases. We further identify an integrability obstruction showing that admissibility alone does not guarantee properness. Two nonlinear examples illustrate the constructions and demonstrate safe stabilization in cases where feedback based on the original CLF violates the safety constraint.
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Systems and Control
Mixed-integer optimization for multi-year military aircraft fleet management
Matteo Vescovi, Raffaele Giuseppe Cestari, Roberto Valdambrini et al. (+3 more)
While existing strategies for Flight and Maintenance Planning for the defense sector generally address idealized conditions, real-world planning often involve non-nominal initial fleet states and complex inspection schemes. To address these challenges, we propose a multi-year planning strategy that maximizes long-term fleet availability. The formulation incorporates multiple competing objectives capturing the tight coupling between aircraft usage and maintenance, while enforcing cyclic inspection requirements and limited maintenance-dock capacity. To enhance practical applicability, we introduce three complementary strategies: a receding-horizon approach to reduce computational burden, a
Bayesian Optimization routine to automatically tune cost-function coefficients, and an aircraft-specific weighting scheme that adapts model priorities based on fleet-condition statistics. Results on three realistic
benchmark scenarios demonstrate the effectiveness of the approach.
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All authors Matteo Vescovi, Raffaele Giuseppe Cestari, Roberto Valdambrini, Andrea Mercurio, Valentina Breschi, Mara Tanelli