Systems and Control · Cross-listed from cs.CE
Design-OS: A Specification-Driven Framework for Engineering System Design with a Control-Systems Design Case
H. Sinan Bank, Daniel R. Herber and Thomas H. Bradley
Engineering system design – whether mechatronic, control, or embedded – often proceeds in an ad hoc manner, with requirements left implicit and traceability from intent to parameters largely absent. Existing specification-driven and systematic design methods mostly target software, and AI-assisted tools tend to enter the workflow at solution generation rather than at problem framing. Human–AI collaboration in the design of physical systems remains underexplored. This paper presents Design-OS, a lightweight, specification-driven workflow for engineering system design organized in five stages: concept definition, literature survey, conceptual design, requirements definition, and design definition. Specifications serve as the shared contract between human designers and AI
agents; each stage produces structured artifacts that maintain traceability and support
agent-augmented execution. We position Design-OS relative to requirements-driven design, systematic design frameworks, and AI-assisted design pipelines, and demonstrate it on a control systems design case using two rotary inverted pendulum platforms – an open-source SimpleFOC reaction wheel and a commercial Quanser Furuta pendulum – showing how the same specification-driven workflow accommodates fundamentally different implementations. A blank template and the full design-case artifacts are shared in a public repository to support reproducibility and reuse. The workflow makes the design process visible and auditable, and extends specification-driven orchestration of AI from software to physical engineering system design.
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Systems and Control
A Controller Synthesis Framework for Weakly-Hard Control Systems
Marc Seidel, Martina Maggio and Frank Allgöwer
Deadline misses are more common in real-world systems than one may expect. The weakly-hard task model has become a standard abstraction to describe and analyze how often these misses occur, and has been especially used in control applications. Most existing control approaches check whether a controller manages to stabilize the system it controls when its implementation occasionally misses deadlines. However, they usually do not incorporate deadline-overrun knowledge during the controller synthesis process. In this paper, we present a framework that explicitly integrates weakly-hard constraints into the control design. Our method supports various overrun handling strategies and guarantees stability and performance under weakly-hard constraints. We validate the synthesized controllers on a Furuta pendulum, a representative control
benchmark. The results show that constraint-aware controllers significantly outperform traditional designs, demonstrating the benefits of proactive and informed synthesis for overrun-aware real-time control.
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Systems and Control
Distributed State Estimation for Discrete-time LTI Systems: the Design Trilemma and a Novel Framework
Ruixuan Zhao, Guitao Yang, James Fleming et al. (+1 more)
With the advancement of IoT technologies and the rapid expansion of cyber-physical systems, there is increasing interest in distributed state estimation, where multiple sensors collaboratively monitor large-scale dynamic systems. Compared with its continuous-time counterpart, a discrete-time distributed observer faces greater challenges, as it cannot exploit high-gain mechanisms or instantaneous communication. Existing approaches depend on three tightly coupled factors: (i) system observability, (ii) communication frequency and dimension of the exchanged information, and (iii) network connectivity. However, the interdependence among these factors remains underexplored. This paper identifies a fundamental trilemma among these factors and introduces a general design framework that balances them through an iterative semidefinite programming approach. As such, the proposed method mitigates the restrictive assumptions present in existing works. The effectiveness and generality of the proposed approach are demonstrated through a simulation example.
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All authors Ruixuan Zhao, Guitao Yang, James Fleming, Boli Chen
Systems and Control
An Agentic Multi-Agent Architecture for Cybersecurity Risk Management
Ravish Gupta, Saket Kumar, Shreeya Sharma et al. (+2 more)
Getting a real cybersecurity risk assessment for a small organization is expensive – a NIST CSF-aligned engagement runs $15,000 on the low end, takes weeks, and depends on practitioners who are genuinely scarce. Most small companies skip it entirely. We built a six-
agent AI system where each
agent handles one analytical stage: profiling the organization, mapping assets, analyzing threats, evaluating controls, scoring risks, and generating recommendations.
Agents share a persistent context that grows as the assessment proceeds, so later
agents build on what earlier ones concluded – the mechanism that distinguishes this from standard sequential
agent pipelines. We tested it on a 15-person HIPAA-covered healthcare company and compared outputs to independent assessments by three CISSP practitioners – the system agreed with them 85% of the time on severity classifications, covered 92% of identified risks, and finished in under 15 minutes. We then ran 30 repeated single-
agent assessments across five synthetic but sector-realistic organizational profiles in healthcare, fintech, manufacturing, retail, and SaaS, comparing a general-purpose Mistral-7B against a domain fine-tuned model. Both completed every run. The fine-tuned model flagged threats the baseline could not see at all: PHI exposure in healthcare, OT/IIoT vulnerabilities in manufacturing, platform-specific risks in retail. The full multi-
agent pipeline, however, failed every one of 30 attempts on a Tesla T4 with its 4,096-
token default context window – context capacity, not model quality, turned out to be the binding constraint.
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All authors Ravish Gupta, Saket Kumar, Shreeya Sharma, Maulik Dang, Abhishek Aggarwal
Audio and Speech Processing
BioDCASE 2026 Challenge Baseline for Cross-Domain Mosquito Species Classification
Yuanbo Hou, Vanja Zdravkovic, Marianne Sinka et al. (+5 more)
Mosquito-borne diseases affect more than one billion people each year and cause close to one million deaths. Traditional surveillance methods rely on traps and manual identification that are slow, labor-intensive, and difficult to scale. Audio-based mosquito monitoring offers a non-destructive, lower-cost, and more scalable complement to trap-based surveillance, but reliable species classification remains difficult under real-world recording conditions. Mosquito flight tones are narrow-band, often low in signal-to-noise ratio, and easily masked by background noise, and recordings for several epidemiologically relevant species remain limited, creating pronounced class imbalance. Variation across devices, environments, and collection protocols further increases the difficulty of robust classification. Such variation can cause models to rely on domain-specific recording artefacts rather than species-relevant acoustic cues, which makes transfer to new acquisition settings difficult. The BioDCASE 2026 Cross-Domain Mosquito Species Classification (CD-MSC) challenge is designed around this deployment problem by evaluating performance on both seen and unseen domains. This paper presents the official baseline system and evaluation pipeline as a simple, fully reproducible reference for the CD-MSC challenge task. The baseline uses log-mel features and a multitemporal resolution convolutional neural network (MTRCNN) with species and auxiliary domain outputs, together with complete training and test scripts. The baseline system performs strongly on seen domains but degrades markedly on unseen domains, showing that cross-domain generalisation, rather than within-domain recognition, is the central challenge for practical mosquito species classification from multi-source bioacoustic recordings.
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All authors Yuanbo Hou, Vanja Zdravkovic, Marianne Sinka, Yunpeng Li, Wenwu Wang, Mark D. Plumbley, Kathy Willis, Stephen Roberts
Image and Video Processing · Cross-listed from cs.CV
A Unified Platform and Quality Assurance Framework for 3D Ultrasound Reconstruction with Robotic, Optical, and Electromagnetic Tracking
Lewis Howell, Manisha Waterston, Tze Min Wah et al. (+2 more)
Three-dimensional (3D) Ultrasound (US) can facilitate diagnosis, treatment planning, and image-guided therapy. However, current studies rarely provide a comprehensive evaluation of volumetric accuracy and reproducibility, highlighting the need for robust Quality Assurance (QA) frameworks, particularly for tracked 3D US reconstruction using freehand or robotic acquisition. This study presents a QA framework for 3D US reconstruction and a flexible open source platform for tracked US research. A custom phantom containing
geometric inclusions with varying
symmetry properties enables straightforward evaluation of optical, electromagnetic, and robotic kinematic tracking for 3D US at different scanning speeds and insonation angles. A standardised pipeline performs real-time
segmentation and 3D reconstruction of
geometric targets (DSC = 0.97, FPS = 46) without GPU acceleration, followed by automated registration and comparison with ground-truth geometries. Applying this framework showed that our robotic 3D US achieves state-of-the-art reconstruction performance (DSC-3D = 0.94 +- 0.01, HD95 = 1.17 +- 0.12), approaching the spatial resolution limit imposed by the transducer. This work establishes a flexible experimental platform and a reproducible validation methodology for 3D US reconstruction. The proposed framework enables robust cross-platform comparisons and improved reporting practices, supporting the safe and effective clinical translation of 3D ultrasound in diagnostic and image-guided therapy applications.
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All authors Lewis Howell, Manisha Waterston, Tze Min Wah, James H. Chandler, James R. McLaughlan
Signal Processing · Cross-listed from quant-ph
Antenna Array Beamforming Based on a Hybrid Quantum Optimization Framework
Shuai Zeng
This paper proposes a hybrid
quantum optimization framework for large-scale
antenna-array beamforming with jointly optimized discrete phases and continuous amplitudes. The method combines
quantum-inspired search with classical gradient refinement to handle mixed discrete-continuous variables efficiently. For phase optimization, a Gray-code and odd-combination encoding scheme is introduced to improve robustness and avoid the complexity explosion of higher-order Ising models. For amplitude optimization, a
geometric spin-combination encoding and a two-stage strategy are developed, using
quantum-inspired optimization for coarse search and gradient optimization for fine refinement. To enhance solution diversity and quality, a rainbow
quantum-inspired
algorithm integrates multiple optimizers for parallel exploration, followed by hierarchical-clustering-based candidate refinement. In addition, a double outer-product method and an augmented version are proposed to construct the coupling
matrix and bias vector efficiently, improving numerical precision and implementation efficiency. Under the scoring rules of the 7th National
Quantum Computing Hackathon, simulations on a 32-element
antenna array show that the proposed method achieves a score of 461.58 under constraints on near-main-lobe sidelobes, wide-angle sidelobes, beamwidth, and optimization time, nearly doubling the baseline score. The proposed framework provides an effective reference for beamforming optimization in future wireless communication systems.
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Systems and Control
Grid-Constrained Smart Charging of Large EV Fleets: Comparative Study of Sequential DP and a Full Fleet Solver
Ipek Kuvvetli, Christofer Sundström, Sogol Kharrazi et al. (+1 more)
This paper presents a comparative optimization framework for smart charging of electrified vehicle fleets. Using heuristic sequential dynamic programming (SeqDP), the framework minimizes electricity costs while adhering to constraints related to the power grid, charging infrastructure, vehicle availability, and simple considerations of battery aging. Based on real-world operational data, the model incorporates discrete energy states, time-varying tariffs, and state-of-charge (SoC) targets to deliver a scalable and cost-effective solution. Classical DP approach suffers from exponential computational complexity as the problem size increases. This becomes particularly problematic when conducting monthly-scale analyses aimed at minimizing peak power demand across all vehicles. The extended time horizon, coupled with multi-state decision-making, renders exact optimization impractical at larger scales. To address this, a heuristic method is employed to enable systematic aggregation and tractable computation for the Non-Linear Programming (NLP) problem. Rather than seeking a globally optimal solution, this study focuses on a time-efficient smart charging strategy that aims to minimize energy cost while flattening the overall power profile. In this context, a sequential heuristic DP approach is proposed. Its performance is evaluated against a full-fleet solver using Gurobi, a widely used commercial solver in both academia and industry. The proposed
algorithm achieves a reduction of the overall cost and peak power by more than 90% compared to uncontrolled schedules. Its relative cost remains within 9% of the optimal values obtained from the full-fleet solver, and its relative peak-power deviation stays below 15% for larger fleets.
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All authors Ipek Kuvvetli, Christofer Sundström, Sogol Kharrazi, Erik Frisk
Signal Processing
Structured Latent Dynamics in Wireless CSI via Homomorphic World Models
Salmane Naoumi, Mehdi Bennis and Marwa Chafii
We introduce a self-supervised framework for learning predictive and structured representations of wireless channels by modeling the temporal
evolution of channel state information (CSI) in a compact latent space. Our method casts the problem as a world modeling task and leverages the Joint
Embedding Predictive Architecture (JEPA) to learn action-conditioned latent dynamics from CSI trajectories. To promote
geometric consistency and compositionality, we parameterize transitions using homomorphic updates derived from Lie
algebra, yielding a structured latent space that reflects spatial layout and user motion. Evaluations on the DICHASUS
dataset show that our approach outperforms strong baselines in preserving
topology and
forecasting future
embeddings across unseen environments. The resulting latent space enables metrically faithful channel charts, offering a scalable foundation for downstream applications such as mobility-aware scheduling, localization, and wireless scene understanding.
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Image and Video Processing
Investigating a Policy-Based Formulation for Endoscopic Camera Pose Recovery
Jan Emily Mangulabnan, Akshat Chauhan, Laura Fleig et al. (+7 more)
In endoscopic surgery, surgeons continuously locate the endoscopic view relative to the anatomy by interpreting the evolving visual appearance of the intraoperative scene in the context of their prior knowledge.
Vision-based
navigation systems seek to replicate this capability by recovering camera pose directly from endoscopic
video, but most approaches do not embody the same principles of
reasoning about new frames that makes surgeons successful. Instead, they remain grounded in feature matching and
geometric optimization over keyframes, an approach that has been shown to degrade under the challenging conditions of endoscopic imaging like low texture and rapid illumination changes. Here, we pursue an alternative approach and investigate a policy-based formulation of endoscopic camera pose recovery that seeks to imitate experts in estimating trajectories conditioned on the previous camera state. Our approach directly predicts short-horizon relative motions without maintaining an explicit
geometric representation at inference time. It thus addresses, by design, some of the notorious challenges of geometry-based approaches, such as brittle correspondence matching, instability in texture-sparse regions, and limited pose coverage due to reconstruction failure. We evaluate the proposed formulation on cadaveric sinus endoscopy. Under oracle state conditioning, we compare short-horizon motion prediction quality to
geometric baselines achieving lowest mean translation error and competitive rotational accuracy. We analyze robustness by grouping prediction windows according to texture richness and illumination change indicating reduced sensitivity to low-texture conditions. These findings suggest that a learned motion policy offers a viable alternative formulation for endoscopic camera pose recovery.
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All authors Jan Emily Mangulabnan, Akshat Chauhan, Laura Fleig, Lalithkumar Seenivasan, Roger D. Soberanis-Mukul, S. Swaroop Vedula, Russell H. Taylor, Masaru Ishii, Gregory D. Hager, Mathias Unberath
Systems and Control
Predictor-Feedback Stabilization of Linear Switched Systems with State-Dependent Switching and Input Delay
Andreas Katsanikakis, Nikolaos Bekiaris-Liberis and Delphine Bresch-Pietri
We develop a predictor-feedback control design for a class of linear systems with state-dependent switching. The main ingredient of our design is a novel construction of an exact predictor state. Such a construction is possible as for a given, state-dependent switching rule, an implementable formula for the predictor state can be derived in a way analogous to the case of nonlinear systems with input delay. We establish uniform exponential stability of the corresponding closed-loop system via a novel construction of multiple Lyapunov functionals, relying on a backstepping transformation that we introduce. We validate our design in simulation considering a switching rule motivated by communication networks.
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Systems and Control
Steady State Distributed Kalman Filter
Francisco Rego
This paper addresses the synthesis of an optimal fixed-gain distributed observer for discrete-time linear systems over wireless sensor networks. The proposed approach targets the steady-state estimation regime and computes fixed observer gains offline from the asymptotic error covariance of the global distributed BLUE
estimator. Each node then runs a local observer that exchanges only state estimates with its neighbors, without propagating error covariances or performing online information fusion. Under collective observability and strong network connectivity, the resulting distributed observer achieves optimal asymptotic performance among fixed-gain schemes. In comparison with covariance intersection-based methods, the proposed design yields strictly lower steady state estimation error covariance while requiring minimal communication. Numerical simulations illustrate the effectiveness of the approach and its advantages in terms of accuracy and implementation simplicity.
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Signal Processing
Performance Analysis and Optimization of FAS-ARIS Communications for 6G: System Modeling and Analytical Insights
Hong-Bae Jeon, Kai-Kit Wong and Chan-Byoung Chae
This paper introduces a unified analytical and optimization framework for fluid
antenna system-active reconfigurable intelligent surface (FAS-ARIS) communications in 6G. By combining the port reconfigurability of FAS with the signal amplification of ARIS, the proposed design enables more flexible control of the propagation environment and enhanced link reliability beyond what passive solutions can offer. We first derive the optimal ARIS amplification gain under a reflection power constraint to maximize the user's signal-to-noise ratio (SNR). Using a block-diagonal
matrix approximation, we obtain a tractable outage expression and a tight independent-
antenna equivalent upper-bound. Building on this, we establish the monotonic relationship between outage and effective channel gain, which enables a closed-form solution for ARIS phase optimization under limited channel state information (CSI). To further improve spectral efficiency, we propose a region-partitioned throughput optimization framework that achieves near-optimal performance without exhaustive search, thereby verifying its low computational complexity. Extensive simulations confirm the accuracy of the analysis and demonstrate consistent gains in outage and throughput compared to baselines.
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Signal Processing
NCR vs. Passive/Active RIS: How Much NCR Amplification is Required to Beat RIS?
Özlem Tuğfe Demir, Ozan Alp Topal, Cicek Cavdar et al. (+1 more)
This paper investigates the fundamental tradeoff between reconfigurable intelligent surfaces (RISs) and network-controlled repeaters (NCRs) in terms of achievable signal-to-noise ratio (SNR). Considering an uplink system with a multi-
antenna base station (BS) and a single-
antenna user equipment (UE), we derive closed-form SNR expressions for passive RIS-, active RIS-, and NCR-assisted communication under line-of-sight propagation between the BS-RIS/NCR and RIS/NCR-UE. Both narrowband and wideband transmissions are analyzed, with and without the presence of a direct BS–UE link. Our analysis reveals a key structural difference: while the SNR achieved with RISs grows unboundedly with the number of RIS elements, the SNR provided by an NCR is fundamentally limited by the UE–repeater channel due to noise amplification. Nevertheless, we show that NCRs can outperform both passive and active RISs when deployed close to the UE, provided that sufficient amplification is available. Numerical results based on realistic path loss models quantify the amplification levels required for NCRs to outperform RISs across different deployment geometries and system dimensions. These findings provide clear design guidelines for the practical integration of RISs and NCRs in future wireless networks.
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All authors Özlem Tuğfe Demir, Ozan Alp Topal, Cicek Cavdar, Emil Björnson
Image and Video Processing
Goal-Oriented Framework for Optical Flow-based Multi-User Multi-Task Video Transmission
Yujie Xu, Shutong Chen, Nan Li et al. (+3 more)
Efficient multi-user multi-task
video transmission is an important research topic within the realm of current wireless communication systems. To reduce the transmission burden and save communication resources, we propose a goal-oriented semantic communication framework for optical flow-based multi-user multi-task
video transmission (OF-GSC). At the transmitter, we design a semantic encoder that consists of a motion extractor and a patch-level optical flow-based semantic representation extractor to effectively identify and select important semantic representations. At the receiver, we design a
transformer-based semantic decoder for high-quality
video reconstruction and
video classification tasks. To minimize the communication time, we develop a deep deterministic policy gradient (DDPG)-based bandwidth allocation
algorithm for multi-user transmission. For
video reconstruction tasks, our OF-GSC framework achieves a significant improvement in the received
video quality, as evidenced by a 13.47% increase in the structural similarity index measure (SSIM) score in comparison to DeepJSCC. For
video classification tasks, OF-GSC achieves a Top-1 accuracy slightly surpassing the performance of VideoMAE with only 25% required data under the same mask ratio of 0.3. For bandwidth allocation optimization, our DDPG-based
algorithm reduces the maximum transmission time by 25.97% compared with the baseline equal-bandwidth allocation scheme.
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All authors Yujie Xu, Shutong Chen, Nan Li, Yansha Deng, Jinhong Yuan, Robert Schober
Image and Video Processing · Cross-listed from cs.CV
Evaluating Test-Time Adaptation For Facial Expression Recognition Under Natural Cross-Dataset Distribution Shifts
John Turnbull, Shivam Grover, Amin Jalali et al. (+1 more)
Deep learning models often struggle under natural distribution shifts, a common challenge in real-world deployments. Test-Time Adaptation (TTA) addresses this by adapting models during inference without labeled source data. We present the first evaluation of TTA methods for FER under natural domain shifts, performing cross-
dataset experiments with widely used FER
datasets. This moves beyond synthetic corruptions to examine real-world shifts caused by differing collection protocols, annotation standards, and demographics. Results show TTA can boost FER performance under natural shifts by up to 11.34%.
Entropy minimization methods such as TENT and SAR perform best when the target distribution is clean. In contrast, prototype adjustment methods like T3A excel under larger distributional distance scenarios. Finally, feature
alignment methods such as SHOT deliver the largest gains when the target distribution is noisier than our source. Our cross-
dataset analysis shows that TTA effectiveness is governed by the distributional distance and the severity of the natural shift across domains.
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All authors John Turnbull, Shivam Grover, Amin Jalali, Ali Etemad
Systems and Control · Cross-listed from cs.DS
Computational Complexity Analysis of Interval Methods in Solving Uncertain Nonlinear Systems
Rudra Prakash, S. Janardhanan and Shaunak Sen
This paper analyzes the computational complexity of validated interval methods for uncertain nonlinear systems and steady-state enclosure. Interval analysis produces guaranteed enclosures that account for uncertainty and round-off, but its adoption is often limited by computational cost in high dimensions. We develop an
algorithm-level worst-case framework that makes explicit the dependence on the problem dimension $n$, the initial search region size $\mathrm{Vol}(X_0)$, the target tolerance $\varepsilon$, and the costs of validated primitives (inclusion-function evaluation, Jacobian evaluation, and interval linear
algebra). Within this framework, we derive worst-case time and space bounds for interval bisection, subdivision$+$filter, interval constraint propagation, interval Newton, and interval Krawczyk, and identify dominant cost drivers. We also show that the computation of the determinant and inverse of interval
matrices via naive Laplace expansion exhibits factorial growth with increasing
matrix dimension, motivating specialized interval linear
algebra. We complement the worst-case bounds with computational results on two application-motivated biochemical steady-state models (a Hill-type regulatory network and an enzyme-saturation-based winner-take-all
circuit) in dimensions $n\in\{2,5,10\}$, including instances that process millions of boxes. The resulting analysis and experiments support the practical design of validated solvers for uncertainty-aware steady-state screening tasks such as robust operating-point certification and multistability assessment.
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Systems and Control · Cross-listed from math.OC
Structural Controllability of Large-Scale Hypergraphs
Joshua Pickard, Xin Mao and Can Chen
Controlling real-world networked systems, including ecological, biomedical, and engineered networks that exhibit higher-order interactions, remains challenging due to inherent nonlinearities and large system scales. Despite extensive studies on graph controllability, the controllability properties of hypergraphs remain largely underdeveloped. Existing results focus primarily on exact controllability, which is often impractical for large-scale hypergraphs. In this article, we develop a structural controllability framework for hypergraphs by modeling hypergraph dynamics as
polynomial dynamical systems. In particular, we extend classical notions of accessibility and dilation from linear graph-based systems to
polynomial hypergraph dynamics and establish a hypergraph-based criterion under which the
topology guarantees satisfaction of classical Lie-algebraic and Kalman-type rank conditions for almost all parameter choices. We further derive a
topology-based lower bound on the minimum number of driver nodes required for structural controllability and leverage this bound to design a scalable driver node selection
algorithm combining dilation-aware initialization via maximum matching with greedy accessibility expansion. We demonstrate the effectiveness and scalability of the proposed framework through numerical experiments on hypergraphs with tens to thousands of nodes and higher-order interactions.
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Systems and Control
On the Capacity of Future Lane-Free Urban Infrastructure
Patrick Malcolm and Klaus Bogenberger
In this paper, the potential capacity and spatial efficiency of future autonomous lane-free traffic in urban environments are explored using a combination of analytical and simulation-based approaches. For lane-free roadways, a simple analytical approach is employed, which shows not only that lane-free traffic offers a higher capacity than lane-based traffic for the same street width, but also that the relationship between capacity and street width is continuous under lane-free traffic. To test the potential capacity and properties of lane-free signal-free intersections (automated intersection management), two approaches were simulated and compared, including a novel approach which we call OptWULF. This approach uses a multi-
agent conflict-based search approach with a low-level planner that uses a combination of optimization and simple window-based reservation. With these simulations, we confirm the continuous relationship between capacity and street width for intersection scenarios. We also show that OptWULF results in an even utilization of the entire drivable area of the street and intersection area. Furthermore, we show that OptWULF is capable of handling asymmetric demand patterns without any substantial loss in capacity compared to symmetric demand patterns.
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Signal Processing
Reduced-Overhead Channel Estimation and Iterative Detection of FTN Signaling Based on Pilot Superimposition and Spectral Interference Alignment
Yuchen Wu and Shinya Sugiura
This paper proposes low-overhead and low-complexity channel estimation (CE) of frequency-domain equalization aided faster-than-Nyquist (FTN) signaling. In the proposed CE scheme, the concept of pilot superimposition is employed, where the FTN block is designed to superimpose pilot symbols with information symbols, and thus, no dedicated time and frequency resources nor guard bands are required, resulting in a 50% reduction of the overhead. Furthermore, interference induced by the pilot superimposition is eliminated by invoking a novel scheme, referred to as spectral interference
alignment, where a data-dependent sequence is subtracted from transmitted information symbols. The theoretical mean-square error (MSE) of the proposed CE is derived, which verifies that the MSE is no longer affected by interference due to the pilot superimposition.
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Image and Video Processing
ReconMIL: Synergizing Latent Space Reconstruction with Bi-Stream Mamba for Whole Slide Image Analysis
Lubin Gan, Jing Zhang, Heng Zhang et al. (+4 more)
Whole slide image (WSI) analysis heavily relies on multiple instance learning (MIL). While recent methods benefit from large-scale foundation models and advanced sequence modeling to capture long-range dependencies, they still struggle with two critical issues. First, directly applying frozen, task-agnostic features often leads to suboptimal separability due to the domain gap with specific histological tasks. Second, relying solely on global aggregators can cause over-smoothing, where sparse but critical diagnostic signals are overshadowed by the dominant background context. In this paper, we present ReconMIL, a novel framework designed to bridge this domain gap and balance global-local feature aggregation. Our approach introduces a Latent Space Reconstruction module that adaptively projects generic features into a compact, task-specific
manifold, improving boundary delineation. To prevent information dilution, we develop a bi-stream architecture combining a Mamba-based global stream for contextual priors and a CNN-based local stream to preserve subtle morphological anomalies. A scale-adaptive selection mechanism dynamically fuses these two streams, determining when to rely on overall architecture versus local saliency. Evaluations across multiple diagnostic and survival prediction
benchmarks show that ReconMIL consistently outperforms current state-of-the-art methods, effectively localizing fine-grained diagnostic regions while suppressing background noise. Visualization results confirm the models superior ability to localize diagnostic regions by effectively balancing global structure and local granularity.
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All authors Lubin Gan, Jing Zhang, Heng Zhang, Xin Di, Zhifeng Wang, Wenke Huang, Xiaoyan Sun
Systems and Control
Learning Adaptive Parameter Policies for Nonlinear Bayesian Filtering
Ondrej Straka, Felipe Giraldo-Grueso and Renato Zanetti
For many nonlinear
Bayesian state estimation problems, the posterior recursion is not analytically tractable, leading to
algorithms that are influenced by numerical approximation errors. These
algorithms depend on parameters that affect the approximation's accuracy and computational cost. The parameters include, for example, the number of particles, scaling parameters, and the number of iterations in iterative computations. Typically, these parameters are fixed or adjusted heuristically, although the approximation accuracy can change over time with the local degree of nonlinearity and uncertainty. The approximation errors introduced at a time step propagate through subsequent updates, affecting the accuracy, consistency, and robustness of future estimates. This paper presents adaptive parameter selection in nonlinear
Bayesian filtering as a sequential decision-making problem, where parameters influence not only the immediate estimation outcome but also the future estimates. The decision-making problem is addressed using reinforcement learning to learn adaptive parameter policies for nonlinear
Bayesian filters. Experiments with the unscented Kalman filter and
stochastic integration filter demonstrate that the learned policies improve both estimate quality and consistency.
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Signal Processing · Cross-listed from cs.IT
Repeater-Aided Over-the-Air Phase Synchronization in Distributed MIMO
Unnikrishnan Kunnath Ganesan, Sai Subramanyam Thoota and Erik G. Larsson
Phase synchronization of access points (APs) in a distributed multiple-input multiple-output (D-
MIMO) system is critical to leverage the performance benefits of D-
MIMO. Existing over-the-air phase synchronization methods assume that APs can communicate directly to perform necessary measurements. However, this assumption might not hold in scenarios where inter-AP signaling is too weak for effective communication. To address this, in this paper, we propose a novel over-the-air calibration scheme that uses repeater nodes to facilitate phase synchronization when direct AP signaling is infeasible. We give the steps of the
algorithm for phase calibration in closed form, and show how it enables coherent joint transmission (CJT) by the APs. The framework expands the applicability of D-
MIMO systems to challenging environments, where existing over-the-air synchronization techniques fall short.
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Systems and Control
Complex Frequency as Generalized Eigenvalue
Nikolas Sofos and Federico Milano
This paper shows that the concept of complex frequency, originally introduced to characterize the dynamics of signals with complex values, constitutes a generalization of
eigenvalues when applied to the states of linear time-invariant (LTI) systems. Starting from the definition of
geometric frequency, which provides a geometrical interpretation of frequency in electric
circuits that admits a natural decomposition into symmetric and antisymmetric components associated with amplitude variation and rotational motion, respectively, we show that complex frequency arises as its restriction to the two-dimensional Euclidean plane. For LTI systems, it is shown that the complex frequencies computed from the system's states subject to a non-isometric transformation, coincide with the original system's
eigenvalues. This equivalence is demonstrated for diagonalizable systems of any order. The paper provides a unified
geometric interpretation of
eigenvalues, bridging classical linear system theory with differential geometry of curves. The paper also highlights that this equivalence does not generally hold for nonlinear systems. On the other hand, the
geometric frequency of the system can always be defined, providing a geometrical interpretation of the system flow. A variety of examples based on linear and nonlinear
circuits illustrate the proposed framework.
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Signal Processing
Supervised Contrastive Learning Framework for Electroencephalography-based Air-writing Recognition
Anant Jain and Ayush Tripathi
Electroencephalography (
EEG) - based air-writing recognition offers a human-computer interaction paradigm by decoding neural activity associated with handwriting movements. Despite its potential, reliable
EEG-based air-writing recognition remains challenging due to low signal-to-noise ratio and pronounced inter-subject variability. In this study, we examine the use of supervised contrastive learning to improve representation learning for
EEG-based air-writing recognition. The analysis is conducted on preprocessed
EEG signals and independent component analysis (ICA)-derived neural components obtained from five participants, with trials segmented from -1 to 2 s relative to movement on-set. EEGNet and DeepConvNet architectures are evaluated under both conventional cross-
entropy training and a supervised contrastive learning framework using a subject-dependent five-fold cross-validation scheme. The results indicate that supervised contrastive learning consistently improves classification accuracy across architectures and feature representations. For preprocessed
EEG signals, the mean accuracy increases from 33.45% to 43.77% and from 29.14% to 38.06% with EEGNet and DeepConvNet, respectively. Using ICA components, higher mean accuracies of 49.21% and 43.32% are achieved with EEGNet and DeepConvNet, respectively. These results suggest that the supervised contrastive learning framework offers an efficient extension to existing
EEG-based air-writing recognition approaches.
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Audio and Speech Processing
Gesture2Speech: How Far Can Hand Movements Shape Expressive Speech?
Lokesh Kumar, Nirmesh Shah, Ashishkumar P. Gudmalwar et al. (+1 more)
Human communication seamlessly integrates
speech and bodily motion, where hand gestures naturally complement vocal prosody to express intent,
emotion, and emphasis. While recent text-to-
speech (TTS) systems have begun incorporating
multimodal cues such as facial expressions or lip movements, the role of hand gestures in shaping prosody remains largely underexplored. We propose a novel
multimodal TTS framework, Gesture2
Speech, that leverages visual gesture cues to modulate prosody in synthesized
speech. Motivated by the observation that confident and expressive speakers coordinate gestures with vocal prosody, we introduce a
multimodal Mixture-of-Experts (MoE) architecture that dynamically fuses linguistic content and gesture features within a dedicated style extraction module. The fused representation conditions an LLM-based
speech decoder, enabling prosodic modulation that is temporally aligned with hand movements. We further design a gesture-
speech alignment loss that explicitly models their temporal correspondence to ensure fine-grained synchrony between gestures and prosodic contours. Evaluations on the PATS
dataset show that Gesture2
Speech outperforms state-of-the-art baselines in both
speech naturalness and gesture-
speech synchrony. To the best of our knowledge, this is the first work to utilize hand gesture cues for prosody control in neural
speech synthesis. Demo samples are available at https://research.sri-media-analysis.com/aaai26-beeu-gesture2
speech/
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All authors Lokesh Kumar, Nirmesh Shah, Ashishkumar P. Gudmalwar, Pankaj Wasnik
Signal Processing
Outlier-Resistant Fusion for Multi-static Positioning using 5G NR Signals
Maximiliano Rivera Figueroa, Jannis Held, Pradyumna Kumar Bishoyi et al. (+1 more)
Indoor positioning faces ongoing challenges due to complex propagation conditions, such as multipath propagation, signal blockages, and intrinsic target characteristics that substantially impact measurement reliability and positioning accuracy. Existing methods, in particular Least Squares (LS), frequently struggle to maintain robustness when confronted with unreliable observations caused by multipath interactions and extended targets. In this work, we propose an outlier-resistant
algorithm designed to mitigate the impact of outlier measurements and accurately estimate the position of an extended target in multipath-rich environments. We develop a two-step
algorithm in which an initial coarse position estimate is obtained using the angle-of-arrival (AoA) and subsequently refined using the Cauchy loss function to suppress outliers. The numerical results confirm that the proposed
algorithm improves robustness and accuracy, outperforming existing
benchmark methods, such as Iterative Reweighted Least Squares (IRLS), LS, and Huber loss function, and achieving a positioning error of less than $70$ cm in $90\%$ of cases. Its effectiveness in mitigating multipath effects is further assessed by comparing tracking performance in cluttered and empty room scenarios.
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All authors Maximiliano Rivera Figueroa, Jannis Held, Pradyumna Kumar Bishoyi, Marina Petrova
Systems and Control
A Spectral Perspective on Stochastic Control Barrier Functions
Inkyu Jang, Chams E. Mballo, Claire J. Tomlin et al. (+1 more)
Stochastic control barrier functions (SCBFs) provide a safety-critical control framework for systems subject to
stochastic disturbances by bounding the probability of remaining within a safe set. However, finding a valid SCBF that explicitly reflects the long-horizon behavior of the true safety probability remains a challenge. This paper addresses this issue by adopting a spectral perspective, utilizing the linear operator that governs the
evolution of the closed-loop system's safety probability. We find that the dominant eigenpair of this Koopman-like operator encodes fundamental safety information of the
stochastic system. The dominant eigenfunction is a natural and valid SCBF, with values that characterize relative asymptotic safety across initial states, while the dominant
eigenvalue indicates the global asymptotic rate at which the safety probability decays. A practical
algorithm for computation is proposed, termed power-policy iteration, which jointly estimates the dominant eigenpair while updating the backup policy with the aim of improving long-term safety. The method is validated using simulation experiments on safety-critical dynamics models.
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All authors Inkyu Jang, Chams E. Mballo, Claire J. Tomlin, H. Jin Kim
Image and Video Processing
Offshore oil and gas platform dynamics in the North Sea, Gulf of Mexico, and Persian Gulf: Exploiting the Sentinel-1 archive
Robin Spanier, Thorsten Hoeser, John Truckenbrodt et al. (+2 more)
The increasing use of marine spaces by offshore infrastructure, including oil and gas platforms, underscores the need for consistent, scalable monitoring. Offshore development has economic, environmental, and regulatory implications, yet maritime areas remain difficult to monitor systematically due to their inaccessibility and spatial extent. This study presents an automated approach to the spatiotemporal detection of offshore oil and gas platforms based on freely available Earth observation data. Leveraging Sentinel-1 archive data and deep learning-based object detection, a consistent quarterly time series of platform locations for three major production regions: the North Sea, the Gulf of Mexico, and the Persian Gulf, was created for the period 2017-2025. In addition, platform size, water depth, distance to the coast, national affiliation, and installation and decommissioning dates were derived. 3,728 offshore platforms were identified in 2025, 356 in the North Sea, 1,641 in the Gulf of Mexico, and 1,731 in the Persian Gulf. While expansion was observed in the Persian Gulf until 2024, the Gulf of Mexico and the North Sea saw a decline in platform numbers from 2018-2020. At the same time, a pronounced dynamic was apparent. More than 2,700 platforms were installed or relocated to new sites, while a comparable number were decommissioned or relocated. Furthermore, the increasing number of platforms with short lifespans points to a structural change in the offshore sector associated with the growing importance of mobile offshore units such as jack-ups or drillships. The results highlighted the potential of freely available Earth observation data and deep learning for consistent, long-term monitoring of marine infrastructure. The derived
dataset is public and provides a basis for offshore monitoring, maritime planning, and analyses of the transformation of the offshore energy sector.
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All authors Robin Spanier, Thorsten Hoeser, John Truckenbrodt, Felix Bachofer, Claudia Kuenzer
Audio and Speech Processing · Cross-listed from cs.SD
Borderless Long Speech Synthesis
Xingchen Song, Di Wu, Dinghao Zhou et al. (+12 more)
Most existing text-to-
speech (TTS) systems either synthesize
speech sentence by sentence and stitch the results together, or drive synthesis from plain-text dialogues alone. Both approaches leave models with little understanding of global context or paralinguistic cues, making it hard to capture real-world phenomena such as multi-speaker interactions (interruptions, overlapping
speech), evolving emotional arcs, and varied acoustic environments. We introduce the Borderless Long
Speech Synthesis framework for
agent-centric, borderless long audio synthesis. Rather than targeting a single narrow task, the system is designed as a unified capability set spanning VoiceDesigner, multi-speaker synthesis, Instruct TTS, and long-form text synthesis. On the data side, we propose a "Labeling over filtering/cleaning" strategy and design a top-down, multi-level annotation schema we call Global-Sentence-
Token. On the model side, we adopt a backbone with a continuous tokenizer and add Chain-of-Thought (CoT)
reasoning together with Dimension Dropout, both of which markedly improve instruction following under complex conditions. We further show that the system is Native Agentic by design: the hierarchical annotation doubles as a Structured Semantic Interface between the LLM
Agent and the synthesis engine, creating a layered control protocol stack that spans from scene semantics down to phonetic detail. Text thereby becomes an information-complete, wide-band control channel, enabling a front-end LLM to convert inputs of any modality into structured generation commands, extending the paradigm from Text2
Speech to borderless long
speech synthesis.
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All authors Xingchen Song, Di Wu, Dinghao Zhou, Pengyu Cheng, Hongwu Ding, Yunchao He, Jie Wang, Shengfan Shen, Sixiang Lv, Lichun Fan, Hang Su, Yifeng Wang, Shuai Wang, Meng Meng, Jian Luan