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Electrical Engineering and Systems Science

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Monday 20 October

Signal Processing

ORIX: Orchestration of RIS with xApps for Smart Wireless Factory Environments

The vision of a smart wireless factory (SWF) demands highly flexible, low-latency, and reliable connectivity that goes beyond conventional wireless solutions. Reconfigurable intelligent surface (RIS)-empowered communications, when integrated with the open radio access network (O-RAN) architectures, have emerged as a promising enabler to meet these challenging requirements. This article introduces the methodology for the orchestration of RIS with xApps (ORIX), bringing the RIS technology into the O-RAN ecosystem through xApp-based control for SWF environments. ORIX features three key components: an O-RAN-compliant RIS service model for dynamic configuration, an RIS channel simulator that supports 3GPP indoor factory models with multiple industrial scenarios, and practical RIS optimization strategies with finite-resolution control. Together, these elements provide a realistic end-to-end emulation platform for evaluating RIS placement, control, and performance in SWF environments prior to deployment. The presented case study demonstrates how ORIX enables the evaluation of achievable performance gains, exploration of trade-offs among key RIS design parameters, and identification of deployment strategies that balance system performance with practical implementation constraints. By bridging theoretical advances with industrial feasibility, ORIX lays the groundwork for RIS-assisted O-RAN networks to power next-generation wireless communication in industrial scenarios.
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All authors Sefa Kayraklik, Ali Fuat Sahin, Onur Salan, Recep A. Tasci, Recep Vural, Yusuf Islam Tek, Ertugrul Basar, Ibrahim Hokelek, Ali Gorcin, Karim Boutiba, Adlen Ksentini

Systems and Control · Cross-listed from physics.med-ph

Inverse Optimal Control of Muscle Force Sharing During Pathological Gait

Muscle force sharing is typically resolved by minimizing a specific objective function to approximate neural control strategies. An inverse optimal control approach was applied to identify the "best" objective function, among a positive linear combination of basis objective functions, associated with the gait of two post-stroke males, one high-functioning (subject S1) and one low-functioning (subject S2). It was found that the "best" objective function is subject- and leg-specific. No single function works universally well, yet the best options are usually differently weighted combinations of muscle activation- and power-minimization. Subject-specific inverse optimal control models performed best on their respective limbs (RMSE 178/213 N, CC 0.71/0.61 for non-paretic and paretic legs of S1; RMSE 205/165 N, CC 0.88/0.85 for respective legs of S2), but cross-subject generalization was poor, particularly for paretic legs. Moreover, minimizing the root mean square of muscle power emerged as important for paretic limbs, while minimizing activation-based functions dominated for non-paretic limbs. This may suggest different neural control strategies between affected and unaffected sides, possibly altered by the presence of spasticity. Among the 15 considered objective functions commonly used in inverse dynamics-based computations, the root mean square of muscle power was the only one explicitly incorporating muscle velocity, leading to a possible model for spasticity in the paretic limbs. Although this objective function has been rarely used, it may be relevant for modeling pathological gait, such as post-stroke gait.
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All authors Filip Bečanović, Vincent Bonnet, Kosta Jovanović, Samer Mohammed, Raphaël Dumas

Image and Video Processing

Segmenting infant brains across magnetic fields: Domain randomization and annotation curation in ultra-low field MRI

Early identification of neurodevelopmental disorders relies on accurate segmentation of brain structures in infancy, a task complicated by rapid brain growth, poor tissue contrast, and motion artifacts in pediatric MRI. These challenges are further exacerbated in ultra-low-field (ULF, 0.064~T) MRI, which, despite its lower image quality, offers an affordable, portable, and sedation-free alternative for use in low-resource settings. In this work, we propose a domain randomization (DR) framework to bridge the domain gap between high-field (HF) and ULF MRI in the context of the hippocampi and basal ganglia segmentation in the LISA challenge. We show that pre-training on whole-brain HF segmentations using DR significantly improves generalization to ULF data, and that careful curation of training labels, by removing misregistered HF-to-ULF annotations from training, further boosts performance. By fusing the predictions of several models through majority voting, we are able to achieve competitive performance. Our results demonstrate that combining robust augmentation with annotation quality control can enable accurate segmentation in ULF data. Our code is available at https://github.com/Medical-Image-Analysis-Laboratory/lisasegm
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All authors Vladyslav Zalevskyi, Dondu-Busra Bulut, Thomas Sanchez, Meritxell Bach Cuadra

Image and Video Processing

AV1 Motion Vector Fidelity and Application for Efficient Optical Flow

This paper presents a comprehensive analysis of motion vectors extracted from AV1-encoded video streams and their application in accelerating optical flow estimation. We demonstrate that motion vectors from AV1 video codec can serve as a high-quality and computationally efficient substitute for traditional optical flow, a critical but often resource-intensive component in many computer vision pipelines. Our primary contributions are twofold. First, we provide a detailed comparison of motion vectors from both AV1 and HEVC against ground-truth optical flow, establishing their fidelity. In particular we show the impact of encoder settings on motion estimation fidelity and make recommendations about the optimal settings. Second, we show that using these extracted AV1 motion vectors as a "warm-start" for a state-of-the-art deep learning-based optical flow method, RAFT, significantly reduces the time to convergence while achieving comparable accuracy. Specifically, we observe a four-fold speedup in computation time with only a minor trade- off in end-point error. These findings underscore the potential of reusing motion vectors from compressed video as a practical and efficient method for a wide range of motion-aware computer vision applications.
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Systems and Control · Cross-listed from cs.RO

Integrating Trustworthy Artificial Intelligence with Energy-Efficient Robotic Arms for Waste Sorting

This paper presents a novel methodology that integrates trustworthy artificial intelligence (AI) with an energy-efficient robotic arm for intelligent waste classification and sorting. By utilizing a convolutional neural network (CNN) enhanced through transfer learning with MobileNetV2, the system accurately classifies waste into six categories: plastic, glass, metal, paper, cardboard, and trash. The model achieved a high training accuracy of 99.8% and a validation accuracy of 80.5%, demonstrating strong learning and generalization. A robotic arm simulator is implemented to perform virtual sorting, calculating the energy cost for each action using Euclidean distance to ensure optimal and efficient movement. The framework incorporates key elements of trustworthy AI, such as transparency, robustness, fairness, and safety, making it a reliable and scalable solution for smart waste management systems in urban settings.
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All authors Halima I. Kure, Jishna Retnakumari, Augustine O. Nwajana, Umar M. Ismail, Bilyaminu A. Romo, Ehigiator Egho-Promise

Signal Processing · Cross-listed from cs.LG

Multi-Window Temporal Analysis for Enhanced Arrhythmia Classification: Leveraging Long-Range Dependencies in Electrocardiogram Signals

Objective. Arrhythmia classification from electrocardiograms (ECGs) suffers from high false positive rates and limited cross-dataset generalization, particularly for atrial fibrillation (AF) detection where specificity ranges from 0.72 to 0.98 using conventional 30-s analysis windows. While most deep learning approaches analyze isolated 30-s ECG windows, many arrhythmias, including AF and atrial flutter, exhibit diagnostic features that emerge over extended time scales. Approach. We introduce S4ECG, a deep learning architecture based on structured state-space models (S4), designed to capture long-range temporal dependencies by jointly analyzing multiple consecutive ECG windows spanning up to 20 min. We evaluate S4ECG on four publicly available databases for multi-class arrhythmia classification and perform systematic cross-dataset evaluations to assess out-of-distribution robustness. Results. Multi-window analysis consistently outperforms single-window approaches across all datasets, improving macro-averaged AUROC by 1.0-11.6 percentage points. For AF, specificity increases from 0.718-0.979 to 0.967-0.998 at a fixed sensitivity threshold, yielding a 3-10-fold reduction in false positive rates. Significance. Compared with convolutional neural network baselines, the S4 architecture shows superior performance, and multi-window training substantially reduces cross-dataset degradation. Optimal diagnostic windows are 10-20 min, beyond which performance plateaus or degrades. These findings demonstrate that structured incorporation of extended temporal context enhances both arrhythmia classification accuracy and cross-dataset robustness. The identified optimal temporal windows provide practical guidance for ECG monitoring system design and may reflect underlying physiological timescales of arrhythmogenic dynamics.
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Systems and Control · Cross-listed from cs.CR

Process Automation Architecture Using RFID for Transparent Voting Systems

This paper presents the development of a process automation architecture leveraging Radio Frequency Identification (RFID) technology for secure, transparent and efficient voting systems. The proposed architecture automates the voting workflow through RFID-enabled voter identification, encrypted vote casting, and secure data transmission. Each eligible voter receives a smart RFID card containing a uniquely encrypted identifier, which is verified using an RC522 reader interfaced with a microcontroller. Upon successful verification, the voter interacts with a touchscreen interface to cast a vote, which is then encrypted using AES-128 and securely stored on a local SD card or transmitted via GSM to a central server. A tamper-proof monitoring mechanism records each session with time-stamped digital signatures, ensuring auditability and data integrity. The architecture is designed to function in both online and offline modes, with an automated batch synchronization mechanism that updates vote records once network connectivity is restored. System testing in simulated environments confirmed 100% voter authentication accuracy, minimized latency (average voting time of 11.5 seconds), and robustness against cloning, double voting, and data interception. The integration of real-time monitoring and secure process control modules enables electoral authorities to automate data logging, detect anomalies, and validate system integrity dynamically. This work demonstrates a scalable, automation-driven solution for voting infrastructure, offering enhanced transparency, resilience, and deployment flexibility, especially in environments where digital transformation of electoral processes is critically needed.
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All authors Stella N. Arinze, Patrick U. Okafor, Onyekachi M. Egwuagu, Augustine O. Nwajana

Signal Processing · Cross-listed from cs.LG

RINS-T: Robust Implicit Neural Solvers for Time Series Linear Inverse Problems

Time series data are often affected by various forms of corruption, such as missing values, noise, and outliers, which pose significant challenges for tasks such as forecasting and anomaly detection. To address these issues, inverse problems focus on reconstructing the original signal from corrupted data by leveraging prior knowledge about its underlying structure. While deep learning methods have demonstrated potential in this domain, they often require extensive pretraining and struggle to generalize under distribution shifts. In this work, we propose RINS-T (Robust Implicit Neural Solvers for Time Series Linear Inverse Problems), a novel deep prior framework that achieves high recovery performance without requiring pretraining data. RINS-T leverages neural networks as implicit priors and integrates robust optimization techniques, making it resilient to outliers while relaxing the reliance on Gaussian noise assumptions. To further improve optimization stability and robustness, we introduce three key innovations: guided input initialization, input perturbation, and convex output combination techniques. Each of these contributions strengthens the framework's optimization stability and robustness. These advancements make RINS-T a flexible and effective solution for addressing complex real-world time series challenges. Our code is available at https://github.com/EPFL-IMOS/RINS-T.
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Systems and Control

Accelerating Adaptive Systems via Normalized Parameter Estimation Laws

In this paper, we propose a new class of parameter estimation laws for adaptive systems, called normalized parameter estimation laws. A key feature of these estimation laws is that they accelerate the convergence of the system state, $\mathit{x(t)}$, to the origin. We quantify this improvement by showing that our estimation laws guarantee finite integrability of the $\mathit{r}$-th root of the squared norm of the system state, i.e., \( \mathit{\|x(t)\|}_2^{2/\mathit{r}} \in \mathcal{L}_1, \) where $\mathit{r} \geq 1$ is a pre-specified parameter that, for a broad class of systems, can be chosen arbitrarily large. In contrast, standard Lyapunov-based estimation laws only guarantee integrability of $\mathit{\|x(t)\|}_2^2$ (i.e., $\mathit{r} = 1$). We motivate our method by showing that, for large values of $r$, this guarantee serves as a sparsity-promoting mechanism in the time domain, meaning that it penalizes prolonged signal duration and slow decay, thereby promoting faster convergence of $\mathit{x(t)}$. The proposed estimation laws do not rely on time-varying or high adaptation gains and do not require persistent excitation. Moreover, they can be applied to systems with matched and unmatched uncertainties, regardless of their dynamic structure, as long as a control Lyapunov function (CLF) exists. Finally, they are compatible with any CLF-based certainty equivalence controllers. We further develop higher-order extensions of our estimation laws by incorporating momentum into the estimation dynamics. We illustrate the performance improvements achieved with the proposed scheme through various numerical experiments.
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Signal Processing

Efficiency-Enhanced Open Earbud Earphone Antenna Using Dual-Feed Technique

The stringent spatial constraints and the demand for high antenna efficiency in modern wireless earphones present significant design challenges. To address these issues, this paper presents and thoroughly investigates a novel earphone antenna design specifically tailored for open earbud wireless earphones. In contrast to traditional earphone antennas that rely on a conventional single-feed configuration, the proposed design introduces a dual-feed excitation technique incorporating a controlled phase difference between the two feeds. This innovative feeding strategy effectively enlarges the equivalent radiating aperture, thereby enhancing the overall radiation efficiency of the antenna system. Experimental and simulation results demonstrate that the dual-feed approach yields an efficiency improvement exceeding 1 dB when compared with standard single-feed designs. Furthermore, the fabricated prototype achieves a -6 dB impedance bandwidth that fully encompasses the 2.4 GHz ISM band, ensuring stable wireless communication performance. The measured total efficiencies reach -8.5 dB in free space and -9.5 dB under on-head conditions. These results confirm that the proposed antenna successfully achieves high efficiency and reliable performance within the extremely limited volume of an earbud device, demonstrating strong potential for integration into next-generation compact wireless earphones.
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Systems and Control · Cross-listed from math.OC

Assessing the Quality of a Set of Basis Functions for Inverse Optimal Control via Projection onto Global Minimizers

Inverse optimization (Inverse optimal control) is the task of imputing a cost function such that given test points (trajectories) are (nearly) optimal with respect to the discovered cost. Prior methods in inverse optimization assume that the true cost is a convex combination of a set of convex basis functions and that this basis is consistent with the test points. However, the consistency assumption is not always justified, as in many applications the principles by which the data is generated are not well understood. This work proposes using the distance between a test point and the set of global optima generated by the convex combinations of the convex basis functions as a measurement for the expressive quality of the basis with respect to the test point. A large minimal distance invalidates the set of basis functions. The concept of a set of global optima is introduced and its properties are explored in unconstrained and constrained settings. Upper and lower bounds for the minimum distance in the convex quadratic setting are implemented by bi-level gradient descent and an enriched linear matrix inequality respectively. Extensions to this framework include max-representable basis functions, nonconvex basis functions (local minima), and applying polynomial optimization techniques.
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All authors Filip Bečanović, Jared Miller, Vincent Bonnet, Kosta Jovanović, Samer Mohammed

Systems and Control

Comparison and performance analysis of dynamic encrypted control approaches

Encrypted controllers using homomorphic encryption have proven to guarantee the privacy of measurement and control signals, as well as system and controller parameters, while regulating the system as intended. However, encrypting dynamic controllers has remained a challenge due to growing noise and overflow issues in the encoding. In this paper, we review recent approaches to dynamic encrypted control, such as bootstrapping, periodic resets of the controller state, integer reformulations, and FIR controllers, and equip them with a stability and performance analysis to evaluate their suitability. We complement the analysis with a numerical performance comparison on a benchmark system.
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Signal Processing

When 5G NTN Meets GNSS: Tracking GNSS Signals under Overlaid 5G Waveforms

Global Navigation Satellite Systems (GNSS) provide the backbone of Positioning, Navigation, and Timing (PNT) but remain vulnerable to interference. Low Earth Orbit (LEO) constellations within Fifth-Generation (5G) Non-Terrestrial Networks (NTN) can enhance resilience by jointly supporting communication and navigation. This paper presents the first quantitative analysis of GNSS tracking and navigation message demodulation under a hybrid waveform where a low-power Direct-Sequence Spread Spectrum (DSSS) component is overlaid on an Orthogonal Frequency-Division Multiplexing (OFDM) 5G downlink. We evaluate a minimally modified GNSS receiver that tracks a legacy Global Positioning System (GPS) L1 Coarse/Acquisition (C/A) overlay aligned with 5G frames while treating the 5G waveform as structured interference. Using Monte Carlo simulations under realistic LEO Doppler dynamics, we analyze the Bit Error Rate (BER) of GPS L1 C/A navigation bits and the subframe decoding probability versus Signalto- Interference-plus-Noise Ratio (SINR) for multiple Signalto- Interference Ratios (SIR) and dynamic classes. Results show reliable demodulation across wide SINR ranges for low and medium dynamics, whereas high dynamics impose strict lock limits. These findings confirm the feasibility of Joint Communication and Positioning (JCAP) using a near-legacy GNSS chipset with minimal receiver modifications.
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All authors Idir Edjekouane, Alejandro González Garrido, Jorge Querol, Symeon Chatzinotas

Systems and Control · Cross-listed from math.OC

A polynomial-based QCQP solver for encrypted optimization

In this paper, we present a novel method for solving a class of quadratically constrained quadratic optimization problems using only additions and multiplications. This approach enables solving constrained optimization problems on private data since the operations involved are compatible with the capabilities of homomorphic encryption schemes. To solve the constrained optimization problem, a sequence of polynomial penalty functions of increasing degree is introduced, which are sufficiently steep at the boundary of the feasible set. Adding the penalty function to the original cost function creates a sequence of unconstrained optimization problems whose minimizer always lies in the admissible set and converges to the minimizer of the constrained problem. A gradient descent method is used to generate a sequence of iterates associated with these problems. For the algorithm, it is shown that the iterate converges to a minimizer of the original problem, and the feasible set is positively invariant under the iteration. Finally, the method is demonstrated on an illustrative cryptographic problem, finding the smaller value of two numbers, and the encrypted implementability is discussed.
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All authors Sebastian Schlor, Andrea Iannelli, Junsoo Kim, Hyungbo Shim, Frank Allgöwer

Systems and Control

Enhanced Ground-Satellite Direct Access via Onboard Rydberg Atomic Quantum Receivers

Ground-satellite links for 6G networks face critical challenges, including severe path loss, tight size-weight-power limits, and congested spectrum, all of which significantly hinder the performance of traditional radio frequency (RF) front ends. This article introduces the Rydberg Atomic Quantum Receiver (RAQR) for onboard satellite systems, a millimeter-scale front end that converts radio fields to optical signals through atomic electromagnetically induced transparency. RAQR's high sensitivity and high frequency selectivity address link budget, payload, and interference challenges while fitting within space constraints. A hybrid atomic-electronic design and supporting signal model demonstrate enhanced data rate, coverage, and sensing accuracy relative to conventional RF receivers. The article concludes with integration strategies, distributed-satellite concepts, and open research problems for bringing RAQR-enabled satellite payloads into service.
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All authors Qihao Peng, Tierui Gong, Zihang Song, Qu Luo, Zihuai Lin, Pei Xiao, Chau Yuen

Systems and Control · Cross-listed from cs.LG

Breaking and Fixing Defenses Against Control-Flow Hijacking in Multi-Agent Systems

Control-flow hijacking attacks manipulate orchestration mechanisms in multi-agent systems into performing unsafe actions that compromise the system and exfiltrate sensitive information. Recently proposed defenses, such as LlamaFirewall, rely on alignment checks of inter-agent communications to ensure that all agent invocations are "related to" and "likely to further" the original objective. We start by demonstrating control-flow hijacking attacks that evade these defenses even if alignment checks are performed by advanced LLMs. We argue that the safety and functionality objectives of multi-agent systems fundamentally conflict with each other. This conflict is exacerbated by the brittle definitions of "alignment" and the checkers' incomplete visibility into the execution context. We then propose, implement, and evaluate ControlValve, a new defense inspired by the principles of control-flow integrity and least privilege. ControlValve (1) generates permitted control-flow graphs for multi-agent systems, and (2) enforces that all executions comply with these graphs, along with contextual rules (generated in a zero-shot manner) for each agent invocation.
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All authors Rishi Jha, Harold Triedman, Justin Wagle, Vitaly Shmatikov

Signal Processing

Robust Beamforming Optimization for STAR-RIS Empowered Multi-User RSMA Under Hardware Imperfections and Channel Uncertainty

This study explores the synergy between rate-splitting multiple access (RSMA) and simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) as a unified framework to enable ubiquitous, intelligent, and resilient connectivity in future sixth-generation networks, while improving spectral and energy efficiency. Specifically, we investigate a STAR-RIS-assisted multi-user RSMA system and develop an intelligent optimization strategy that jointly designs the transmitter's active beamforming, the common stream rate allocation, and the passive beamforming vectors for the STAR-RIS transmission and reflection regions, considering transceiver hardware impairments and imperfect channel state information (CSI). In addition, system robustness is ensured via a bounded channel estimation error model that captures CSI imperfections and guarantees resilience against worst-case errors. To address the highly non-convex problem, we propose an iterative optimization algorithm that decomposes it into two sub-problems. Firstly, active beamforming vectors for the common and private signals are determined by reformulating the original problem into a convex semi-definite programming (SDP) form using successive convex approximation (SCA) and semi-definite relaxation (SDR). Secondly, passive beamforming vectors are optimized through a convex SDP reformulation by exploiting SCA and SDR techniques. Moreover, when higher-rank solutions arise, Gaussian randomization is applied to obtain rank-one solutions. Numerical simulations demonstrate that the proposed strategy achieves significant performance gains over benchmark schemes and exhibits fast convergence.
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All authors Muhammad Asif, Asim Ihsan, Zhu Shoujin, Ali Ranjha, Xingwang Li, Khaled M. Rabie, Symeon Chatzinotas

Systems and Control · Cross-listed from cs.RO

Floating-Base Deep Lagrangian Networks

Grey-box methods for system identification combine deep learning with physics-informed constraints, capturing complex dependencies while improving out-of-distribution generalization. Despite the growing importance of floating-base systems such as humanoids and quadrupeds, current grey-box models ignore their specific physical constraints. For instance, the inertia matrix is not only positive definite but also exhibits branch-induced sparsity and input independence. Moreover, the 6x6 composite spatial inertia of the floating base inherits properties of single-rigid-body inertia matrices. As we show, this includes the triangle inequality on the eigenvalues of the composite rotational inertia. To address the lack of physical consistency in deep learning models of floating-base systems, we introduce a parameterization of inertia matrices that satisfies all these constraints. Inspired by Deep Lagrangian Networks (DeLaN), we train neural networks to predict physically plausible inertia matrices that minimize inverse dynamics error under Lagrangian mechanics. For evaluation, we collected and released a dataset on multiple quadrupeds and humanoids. In these experiments, our Floating-Base Deep Lagrangian Networks (FeLaN) achieve better overall performance on both simulated and real robots, while providing greater physical interpretability.
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All authors Lucas Schulze, Juliano Decico Negri, Victor Barasuol, Vivian Suzano Medeiros, Marcelo Becker, Jan Peters, Oleg Arenz

Systems and Control

Generalized Group Selection Strategies for Self-sustainable RIS-aided Communication

Reconfigurable intelligent surface (RIS) is a cutting-edge communication technology that has been proposed as aviable option for beyond fifth-generation wireless communication networks. This paper investigates various group selection strategies in the context of grouping-based self-sustainable RIS-aided device-to-device (D2D) communication with spatially correlated wireless channels. Specifically, we consider both power splitting (PS) and time switching (TS) configurations, of the self-sustainable RIS to analyze the system performance and propose appropriate bounds on the choice of system parameters. The analysis takes into account a simplified linear energy harvesting (EH) model as well as a practical non-linear EH model. Based on the application requirements, we propose various group selection strategies at the RIS. Notably, each strategy schedules the k-th best available group at the RIS based on the end-to-end signal-to-noise ratio (SNR) and also the energy harvested at a particular group of the RIS. Accordingly, by using tools from high order statistics, we derive analytical expressions for the outage probability of each selection strategy. Moreover, by applying the tools from extreme value theory, we also investigate an asymptotic scenario, where the number of groups available for selection at an RIS approaches infinity. The nontrivial insights obtained from this approach is especially beneficial in applications like large intelligent surface-aided wireless communication. Finally, the numerical results demonstrate the importance and benefits of the proposed approaches in terms of metrics such as the data throughput and the outage (both data and energy) performance.
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Systems and Control

A Data-Driven Framework for Online Mitigation of False Data Injection Signals in Networked Control Systems

This paper introduces a novel two-stage framework for online mitigation of False Data Injection (FDI) signals to improve the resiliency of Networked Control Systems (NCSs) and ensure their safe operation in the presence of malicious activities. The first stage involves meta learning to select a base time series forecasting model within a stacked ensemble learning architecture. This is achieved by converting time series data into scalograms using continuous wavelet transform, which are then split into image frames to generate a scalo-temporal representation of the data and to distinguish between different complexity levels of time series data based on an entropy metric using a convolutional neural network. In the second stage, the selected model mitigates false data injection signals in real-time. The proposed framework's effectiveness is demonstrated through rigorous simulations involving the formation control of differential drive mobile robots. By addressing the security challenges in NCSs, this framework offers a promising approach to maintaining system integrity and ensuring operational safety.
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Systems and Control

Semantic Intelligence: A Bio-Inspired Cognitive Framework for Embodied Agents

Recent advancements in Large Language Models (LLMs) have greatly enhanced natural language understanding and content generation. However, these models primarily operate in disembodied digital environments and lack interaction with the physical world. To address this limitation, Embodied Artificial Intelligence (EAI) has emerged, focusing on agents that can perceive and interact with their surroundings. Despite progress, current embodied agents face challenges in unstructured real-world environments due to insufficient semantic intelligence, which is critical for understanding and reasoning about complex tasks. This paper introduces the Semantic Intelligence-Driven Embodied (SIDE) agent framework, which integrates a hierarchical semantic cognition architecture with a semantic-driven decision-making process. This enables agents to reason about and interact with the physical world in a contextually adaptive manner. The framework is inspired by biological cognitive mechanisms and utilizes bio-inspired principles to design a semantic cognitive architecture that mimics how humans and animals integrate and process sensory information. We present this framework as a step toward developing more intelligent and versatile embodied agents.
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All authors Wenbing Tang, Meilin Zhu, Fenghua Wu, Yang Liu

Signal Processing

Reconfigurable Antenna Arrays: Bridging Electromagnetics and Signal Processing

Reconfigurable antennas (RAs), capable of dynamically adapting their radiation patterns, polarization states, and operating frequencies, have emerged as a promising technology to meet the stringent performance requirements of sixth-generation (6G) wireless networks. This article systematically introduces essential hardware implementations of RAs and investigates advanced array architectures, such as fully-digital and tri-hybrid designs, emphasizing their capability to synergistically integrate electromagnetic (EM) reconfigurability with analog and digital signal processing. By facilitating coordinated beamforming across the EM and signal processing domains, RA arrays offer unprecedented flexibility and adaptability compared to conventional static antenna systems. Representative applications empowered by RA arrays, including integrated sensing and communication (ISAC), physical layer security (PLS), and near-field communications, are highlighted. A case study illustrates the effectiveness of RA arrays in optimizing beam steering, improving link robustness, and alleviating system power consumption. Finally, several open challenges and future research directions are outlined, emphasizing the need for advancements in theoretical modeling, hardware reliability, channel estimation techniques, intelligent optimization methods, and innovative network architectures, to fully realize the transformative impact of RAs in future 6G wireless networks.
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All authors Mengzhen Liu, Ming Li, Rang Liu, Qian Liu, A. Lee Swindlehurst

Signal Processing · Cross-listed from cs.IT

Channel Capacity for FMCW-based Optical Wireless Integrated Sensing and Communication: Asymptotic Analysis and Envelope Design

Optical wireless integrated sensing and communication (OW-ISAC) is rapidly burgeoning as a complement and augmentation to its radio-frequency counterpart. In this paper, the channel capacity is analyzed to guide the design of a coherent OW-ISAC system based on frequency-modulated continuous wave (FMCW). Firstly, the system model of FMCW-based OW-ISAC is recast into an information-theoretic formulation, where an additional harmonic-mean constraint is imposed to ensure the sensing performance. Subsequently, both lower and upper bounds for channel capacity are derived under the imposed sensing constraint, based on which asymptotic expressions for channel capacity are presented for both low and high signal-to-noise-ratio regions. Moreover, the analysis of channel capacity provides guidance for the envelope design based on pulse amplitude modulation, whose capacity-achieving capabilities are demonstrated by numerical results. Furthermore, simulations reveal the trade-off between communication and sensing functionalities. In summary, the analysis of channel capacity under the sensing constraint provides insights into both the optimality and the practicality of OW-ISAC design.
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All authors Yunfeng Wen, Fang Yang, Jian Song, Zhu Han

Systems and Control · Cross-listed from cs.CR

Quantum Key Distribution for Virtual Power Plant Communication: A Lightweight Key-Aware Scheduler with Provable Stability

Virtual power plants (VPPs) are becoming a cornerstone of future grids, aggregating distributed PV, wind, storage, and flexible loads for market participation and real-time balancing. As operations move to minute– and second–level feedback, communication security shifts from a compliance item to an operational constraint: latency, reliability, and confidentiality jointly determine whether dispatch, protection, and settlement signals arrive on time. Conventional PKI and key-rotation schemes struggle with cross-domain, high-frequency messaging and face long-term quantum threats. Quantum key distribution (QKD) offers information-theoretic key freshness, but its key yield is scarce and stochastic, often misaligned with bursty VPP traffic. This paper proposes a key-aware priority and quota framework that treats quantum keys as first-class scheduling resources. The design combines (i) forecast-driven long-term quotas and short-term tokens, (ii) key-aware deficit-round-robin arbitration, (iii) a preemptive emergency key reserve, and (iv) graceful degradation via encryption-mode switching and controlled down-sampling for non-critical traffic. A drift-plus-penalty analysis establishes strong stability under average supply–demand balance with quantifiable bounds on backlog and tail latency, providing interpretable operating guarantees. We build a reproducible testbed on IEEE 33- and 123-bus VPP systems and evaluate normal, degraded, and outage regimes with industry-consistent message classes and TTLs. Against FIFO, fixed-priority, and static-quota baselines, the proposed scheme consistently reduces tail delay and passive timeouts for critical messages, improves per-bit key utility, and enhances power-tracking reliability during key scarcity and regime switches.
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Systems and Control

Differentiating Through Power Flow Solutions for Admittance and Topology Control

The power flow equations relate bus voltage phasors to power injections via the network admittance matrix. These equations are central to the key operational and protection functions of power systems (e.g., optimal power flow scheduling and control, state estimation, protection, and fault location, among others). As control, optimization, and estimation of network admittance parameters are central to multiple avenues of research in electric power systems, we propose a linearization of power flow solutions obtained by implicitly differentiating them with respect to the network admittance parameters. This is achieved by utilizing the implicit function theorem, in which we show that such a differentiation is guaranteed to exist under mild conditions and is applicable to generic power systems (radial or meshed). The proposed theory is applied to derive sensitivities of complex voltages, line currents, and power flows. The developed theory of linearizing the power flow equations around changes in the complex network admittance parameters has numerous applications. We demonstrate several of these applications, such as predicting the nodal voltages when the network topology changes without solving the power flow equations. We showcase the application for continuous admittance control, which is used to increase the hosting capacity of a given distribution network.
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All authors Samuel Talkington, Daniel Turizo, Sergio A. Dorado-Rojas, Rahul K. Gupta, Daniel K. Molzahn

Sunday 19 October

Signal Processing

Monitoring Real-Time ECG Signals on Mobile Systems

This study focuses on the connection of a development kit that enables real-time monitoring of electrocardiogram (ECG) signals using a mobile system. A software developed on the Visual Studio .NET platform reads real-time ECG signals from the human body through non invasive methods and displays them graphically on the mobile system. ECG electrodes placed on specific areas of the body using the method known as Einthoven's triangle. Subsequently, the software initiates data flow through the serial port, and these data displayed as signal values on the mobile device's screen via a graphical interface. When the monitored ECG signals fall below a certain threshold or reach a critical value, the system provides feedback with an alert based on medical data. The developed system is fully portable. Additionally, the implemented system has the potential to form the basis for a multi-purpose system in the future, such as online patient monitoring, patient location tracking, and even initial intervention using the defibrillation method.
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Image and Video Processing

Conformal Lesion Segmentation for 3D Medical Images

Medical image segmentation serves as a critical component of precision medicine, enabling accurate localization and delineation of pathological regions, such as lesions. However, existing models empirically apply fixed thresholds (e.g., 0.5) to differentiate lesions from the background, offering no statistical guarantees on key metrics such as the false negative rate (FNR). This lack of principled risk control undermines their reliable deployment in high-stakes clinical applications, especially in challenging scenarios like 3D lesion segmentation (3D-LS). To address this issue, we propose a risk-constrained framework, termed Conformal Lesion Segmentation (CLS), that calibrates data-driven thresholds via conformalization to ensure the test-time FNR remains below a target tolerance $\varepsilon$ under desired risk levels. CLS begins by holding out a calibration set to analyze the threshold setting for each sample under the FNR tolerance, drawing on the idea of conformal prediction. We define an FNR-specific loss function and identify the critical threshold at which each calibration data point just satisfies the target tolerance. Given a user-specified risk level $\alpha$, we then determine the approximate $1-\alpha$ quantile of all the critical thresholds in the calibration set as the test-time confidence threshold. By conformalizing such critical thresholds, CLS generalizes the statistical regularities observed in the calibration set to new test data, providing rigorous FNR constraint while yielding more precise and reliable segmentations. We validate the statistical soundness and predictive performance of CLS on six 3D-LS datasets across five backbone models, and conclude with actionable insights for deploying risk-aware segmentation in clinical practice.
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All authors Binyu Tan, Zhiyuan Wang, Jinhao Duan, Kaidi Xu, Heng Tao Shen, Xiaoshuang Shi, Fumin Shen

Image and Video Processing · Cross-listed from cs.CV

Person Re-Identification via Generalized Class Prototypes

Advanced feature extraction methods have significantly contributed to enhancing the task of person re-identification. In addition, modifications to objective functions have been developed to further improve performance. Nonetheless, selecting better class representatives is an underexplored area of research that can also lead to advancements in re-identification performance. Although past works have experimented with using the centroid of a gallery image class during training, only a few have investigated alternative representations during the retrieval stage. In this paper, we demonstrate that these prior techniques yield suboptimal results in terms of re-identification metrics. To address the re-identification problem, we propose a generalized selection method that involves choosing representations that are not limited to class centroids. Our approach strikes a balance between accuracy and mean average precision, leading to improvements beyond the state of the art. For example, the actual number of representations per class can be adjusted to meet specific application requirements. We apply our methodology on top of multiple re-identification embeddings, and in all cases it substantially improves upon contemporary results.
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Image and Video Processing

A Low-Complexity View Synthesis Distortion Estimation Method for 3D Video with Large Baseline Considerations

Depth-image-based rendering is a key view synthesis algorithm in 3D video systems, which enables the synthesis of virtual views from texture images and depth maps. An efficient view synthesis distortion estimation model is critical for optimizing resource allocation in real-time applications such as interactive free-viewpoint video and 3D video streaming services. However, existing estimation methods are often computationally intensive, require parameter training, or performance poorly in challenging large baseline configurations. This paper presents a novel, low-complexity, and training-free method to accurately estimate the distortion of synthesized views without performing the actual rendering process. Key contributions include: (1) A joint texture-depth classification method that accurately separates texture image into locally stationary and non-stationary regions, which mitigates misclassifications by using texture-only methods. (2) A novel baseline distance indicator is designed for the compensation scheme for distortions caused by large baseline configurations. (3) A region-based blending estimation strategy that geometrically identifies overlapping, single-view, and mutual disocclusion regions, predicting distortion in synthesized views from two reference views with differing synthesis conditions. Experiments on standard MPEG 3D video sequences validate the proposed method's high accuracy and efficiency, especially in large baseline configurations. This method enables more flexible camera arrangements in 3D content acquisition by accurately predicting synthesis quality under challenging geometric configurations.
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Signal Processing · Cross-listed from cs.NI

Traffic Prioritization Mechanisms for Mission and Time Critical Applications in Industrial Internet of Things

Industrial Internet of Things (IIoT) promises to revolutionize industrial operations and productions through utilizing Machine-to-Machine (M2M) communications. Since each node in such environments generates various types of data with diverse service requirements, MAC protocol holds crucial importance to ensure efficient delivery. In this context, simple to complex MAC schemes are found in literature. This paper focuses on evaluating the performance of two major techniques "slot stealing" and "packet fragmentation" for the IIoT; representative protocols SS-MAC and FROG-MAC have been chosen from each category respectively. We conducted realistic simulations for the two protocols using Contiki. Delay and packet loss comparison for SS-MAC and FROG-MAC indicates the superiority of FROG-MAC due to reduction in the waiting time for urgent traffic. Thus, a simple fragmentation scheme could be deployed for efficient scheduling of heterogenous traffic in the industrial environments.
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