Signal Processing · Cross-listed from cs.AR
Beamspace Equalization for mmWave Massive MIMO: Algorithms and VLSI Implementations
Seyed Hadi Mirfarshbafan and Christoph Studer
Massive multiuser multiple-input multiple-output (
MIMO) and millimeter-wave (mmWave) communication are key physical layer technologies in future wireless systems. Their deployment, however, is expected to incur excessive baseband processing hardware cost and power consumption. Beamspace processing leverages the channel sparsity at mmWave frequencies to reduce baseband processing complexity. In this paper, we review existing beamspace data detection
algorithms and propose new
algorithms as well as corresponding VLSI architectures that reduce data detection power. We present VLSI implementation results for the proposed architectures in a 22nm FDSOI process. Our results demonstrate that a fully-parallelized implementation of the proposed complex sparsity-adaptive equalizer (CSPADE) achieves up to 54% power savings compared to
antenna-domain equalization. Furthermore, our fully-parallelized designs achieve the highest reported throughput among existing massive
MIMO data detectors, while achieving better energy and area efficiency. We also present a sequential multiply-accumulate (MAC)-based architecture for CSPADE, which enables even higher power savings, i.e., up to 66%, compared to a MAC-based
antenna-domain equalizer.
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Signal Processing
Evaluation of Grid-based Uncertainty Propagation for Collaborative Self-Calibration in Indoor Positioning Systems
Paul Schwarzbach and Andrea Jung
Radio-based localization systems conventionally require stationary reference points (e.g. anchors) with precisely surveyed positions, making deployment time-consuming and costly. This paper presents an empirical evaluation of collaborative self-calibration for Ultra-Wideband (UWB) networks, extending a discrete
Bayesian approach based on grid-based uncertainty propagation. The enhanced
algorithm reduces measurement availability requirements while maintaining positioning accuracy through probabilistic state estimation. We validate the approach using real-world data from controlled indoor UWB network experiments with 12 nodes in a static environment. Experimental evaluation demonstrates 0.28~m mean ranging error under line-of-sight conditions and 1.11~m overall ranging error across mixed propagation scenarios, achieving sub-meter positioning accuracy. Results demonstrate the
algorithm's robustness to measurement noise and partial connectivity scenarios typical in industrial deployments. The findings contribute to automated UWB network initialization for indoor positioning applications, reducing infrastructure dependency compared to manual anchor calibration procedures.
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Systems and Control
Formal Verification of Control Lyapunov-Barrier Functions for Safe Stabilization with Bounded Controls
Jun Liu
We present verifiable conditions for synthesizing a single smooth Lyapunov function that certifies both asymptotic stability and safety under bounded controls. These sufficient conditions ensure the strict compatibility of a control barrier function (CBF) and a control Lyapunov function (CLF) on the exact safe set certified by the barrier. An explicit smooth control Lyapunov-barrier function (CLBF) is then constructed via a patching formula that is provably correct by design. Two examples illustrate the computational procedure, showing that the proposed approach is less conservative than sum-of-squares (SOS)-based compatible CBF-CLF designs.
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Image and Video Processing · Cross-listed from cs.CV
Oded Schlesinger, Amirhossein Farzam, J. Matias Di Martino et al. (+1 more)
While
Vision Transformers (ViT) have demonstrated remarkable performance across diverse tasks, their computational demands are substantial, scaling quadratically with the number of processed
tokens. Compact
attention representations, reflecting
token interaction distributions, can guide early detection and reduction of less salient
tokens prior to
attention computation. Motivated by this, we present SParsification with
attentiOn dynamics via
Token relevance (SPOT), a framework for early detection of redundant
tokens within ViTs that leverages
token embeddings, interactions, and
attention dynamics across layers to infer
token importance, resulting in a more context-aware and interpretable relevance detection process. SPOT informs
token sparsification and facilitates the elimination of such
tokens, improving computational efficiency without sacrificing performance. SPOT employs computationally lightweight predictors that can be plugged into various ViT architectures and learn to derive effective input-specific
token prioritization across layers. Its versatile design supports a range of performance levels adaptable to varying resource constraints. Empirical evaluations demonstrate significant efficiency gains of up to 40% compared to standard ViTs, while maintaining or even improving accuracy. Code and models are available at https://github.com/odedsc/SPOT .
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All authors Oded Schlesinger, Amirhossein Farzam, J. Matias Di Martino, Guillermo Sapiro
Systems and Control · Cross-listed from cs.HC
Motivations and Actions of Human-Building Interactions from Environmental Momentary Assessments
Maharshi Pathak, SungKu Kang, Vanessa C. Whittem et al. (+3 more)
The expansion of renewable electricity generation, growing demands due to electrification, greater prevalence of working from home, and increasing frequency and severity of extreme weather events, will place new demands on the electric supply and distribution grid. Broader adoption of demand response programs (DRPs) for the residential sector may help meet these challenges; however, experience shows that occupant overrides in DRPs compromises their effectiveness. There is a lack of formal understanding of how discomfort, routines, and other motivations affect DRP overrides and other related human building interactions (HBI). This paper reports preliminary findings from a study of 20 households in Colorado and Massachusetts, US over three months. Participants responded to ecological momentary assessments (EMA) triggered by thermostat interactions and at random times throughout the day. EMAs included Likert-scale questions of thermal preference, preference intensity, and changes to 7 different activity types that could affect thermal comfort, and an opened ended question about motivations of such actions. Twelve tags were developed to categorize motivation responses and analyzed statistically to identify associations between motivations, preferences, and HBI actions. Reactions to changes in the thermal environment were the most frequently observed motivation, 118 of 220 responses. On the other hand, 47% responses were at least partially motivated by non-thermal factors, suggesting limited utility for occupant behavior models founded solely on thermal comfort. Changes in activity level and clothing were less likely to be reported when EMAs were triggered by thermostat interactions, while fan interactions were more likely. Windows, shades, and portable heater interactions had no significant dependence on how the EMA was triggered.
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All authors Maharshi Pathak, SungKu Kang, Vanessa C. Whittem, Katherine Bassett, Michael B. Kane, David J. Fannon
Systems and Control · Cross-listed from math.DS
On topological properties of closed attractors
Wouter Jongeneel
The notion of an attractor has various definitions in the theory of dynamical systems. Under compactness assumptions, several of those definitions coincide and the theory is rather complete. However, without compactness, the picture becomes blurry. To improve our understanding, we characterize in this work when a closed—not necessarily compact—asymptotically stable attractor on a locally compact metric space is a strong deformation retract of its domain of attraction. This enables a further structural study of feedback stabilization problems.
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Systems and Control
A Decomposition Approach to Solving Numerical Constraint Satisfaction Problems on Directed Acyclic Graphs
Max Mowbray, Nilay Shah and Benoît Chachuat
Certifying feasibility in decision-making, critical in many industries, can be framed as a constraint satisfaction problem. This paper focuses on characterising a subset of parameter values from an a priori set that satisfy constraints on a directed acyclic graph of constituent functions. The main assumption is that these functions and constraints may be evaluated for given parameter values, but they need not be known in closed form and could result from expensive or proprietary simulations. This setting lends itself to using sampling methods to gain an inner approximation of the feasible domain. To mitigate the curse of dimensionality, the paper contributes new methodology to leverage the graph structure for decomposing the problem into lower-dimensional subproblems defined on the respective nodes. The working hypothesis that the Cartesian product of the solution sets yielded by the subproblems will tighten the a priori parameter domain, before solving the full problem defined on the graph, is demonstrated through four case studies relevant to machine learning and engineering. Future research will extend this approach to cyclic graphs and account for parametric uncertainty.
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Image and Video Processing
Domain Adaptation for Camera-Specific Image Characteristics using Shallow Discriminators
Maximiliane Gruber, Jürgen Seiler and André Kaup
Each image acquisition setup leads to its own camera-specific image characteristics degrading the image quality. In learning-based perception
algorithms, characteristics occurring during the application phase, but absent in the training data, lead to a domain gap impeding the performance. Previously, pixel-level domain adaptation through unpaired learning of the pristine-to-distorted mapping function has been proposed. In this work, we propose shallow discriminator architectures to address limitations of these approaches. We show that a smaller receptive field size improves learning of unknown image distortions by more accurately reproducing local distortion characteristics at a low network complexity. In a domain adaptation setup for instance
segmentation, we achieve mean average precision increases over previous methods of up to 0.15 for individual distortions and up to 0.16 for camera-specific image characteristics in a simplified camera model. In terms of number of parameters, our approach matches the complexity of one state of the art method while reducing complexity by a factor of 20 compared to another, demonstrating superior efficiency without compromising performance.
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Systems and Control
Stability of a DC Microgrid with a Nonlinear Nested Control Framework: The Fast Communication Scenario
Cornelia Skaga, Mahdieh S. Sadabadi and Gilbert Bergna-Diaz
As modern power systems continue to evolve into multi-
agent, converter-dominated systems that demand reliable, stable, and optimal control architectures within an expandable framework, this paper investigates scalable stability guarantees of a promising nonlinear communication-reliant control framework for DC microgrids. Particularly, relying on nested control loops; inner decentralized(primary) and outer distributed(secondary), the control configurations are designed to simultaneously achieve proportional current sharing and voltage containment within pre-specified limits, at the converged steady state. By enforcing sufficient time-scale separation at the boarder between the control loops, the system admits a singular perturbation formulation, allowing global exponential stability (G.E.S.) to be established via Lyapunov arguments. Although the theoretical G.E.S. certificate is structurally scalable, the stability guarantees depends on a sufficiently large permanent leakage, introduced in the primary controller. Thus, the results of this paper emphasize the importance of appropriate practical tuning guidelines and electrical parameter selection. The effectiveness of the proposed method is validated through case studies on a low-voltage DC microgrid under load variations and topological changes (and communication time-delays), followed by a small-signal stability analysis.
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Systems and Control · Cross-listed from stat.ML
Infinitesimal Operator World Models: Finite-Sample Guarantees for Offline Reinforcement Learning
Nicolas Hoischen, Petar Bevanda, Max Beier et al. (+3 more)
Continuous-time
stochastic processes underlie many natural and engineered systems. In healthcare, autonomous driving, and industrial control, direct interaction with the environment is often unsafe or impractical, motivating offline reinforcement learning from historical data. However, there is limited statistical understanding of the approximation errors inherent in learning policies from offline
datasets. We address this by linking reinforcement learning to the Hamilton-Jacobi-Bellman equation and proposing an operator-theoretic
algorithm based on a simple dynamic programming recursion. Specifically, we represent our world model in terms of the infinitesimal generator of controlled
diffusion processes learned in a reproducing kernel
Hilbert space. By integrating statistical learning methods and operator theory, we establish global convergence of the value function under sufficiently small generator-approximation error and derive explicit finite-sample guarantees with bounds tied directly to system properties such as smoothness and stability. Our theoretical and proof-of-concept results indicate that operator-based approaches may hold promise for solving offline reinforcement learning using continuous-time optimal control.
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All authors Nicolas Hoischen, Petar Bevanda, Max Beier, Stefan Sosnowski, Boris Houska, Sandra Hirche
Systems and Control
Large-Signal Stability Guarantees for a DC Microgrid with Nested Nonlinear Distributed Control: The Slow Communication Scenario
Cornelia Skaga, Mahdieh S. Sadabadi and Gilbert Bergna-Diaz
The increasing integration of renewable energy sources into electrical grids necessitates a paradigm shift toward advanced control schemes that guarantee safe and stable operations with scalable properties. Accordingly, this paper investigates large-signal stability guarantees for cyber-physical DC microgrids employing a nonlinear distributed consensus-based control scheme to enable coordinated integration and management of distributed generation units within an expandable framework. The proposed control framework adopts nested control loops; inner (decentralized) and outer (distributed), specifically designed to simultaneously achieve uniform voltage containment within pre-specified limits, and proportional current sharing in steady state. Our scalable stability result relies on singular perturbation theory and Lyapunov arguments to prove global exponential stability when imposing a sufficient time-scale separation at the border between the nested control loops, while relying on some practical parameter-setting schemes. The effectiveness and versatility of the proposed control strategy are then validated through time-domain simulations performed on a case-specific low-voltage DC microgrid and the modified IEEE 33-bus radial distribution system. Moreover, a small-signal stability analysis is conducted to derive practical guidelines that enhance the applicability of the method.
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Systems and Control · Cross-listed from cs.LG
Gradient Flow Equations for Deep Linear Neural Networks: A Survey from a Network Perspective
Joel Wendin and Claudio Altafini
The paper surveys recent progresses in understanding the dynamics and loss landscape of the gradient flow equations associated to deep linear neural networks, i.e., the gradient descent training dynamics (in the limit when the step size goes to 0) of deep neural networks missing the activation functions and subject to quadratic loss functions. When formulated in terms of the adjacency
matrix of the neural network, as we do in the paper, these gradient flow equations form a class of converging
matrix ODEs which is nilpotent,
polynomial, isospectral, and with conservation laws. The loss landscape is described in detail. It is characterized by infinitely many global minima and saddle points, both strict and nonstrict, but lacks local minima and maxima. The loss function itself is a positive semidefinite Lyapunov function for the gradient flow, and its level sets are unbounded invariant sets of critical points, with critical values that correspond to the amount of singular values of the input-output data learnt by the gradient along a certain trajectory. The adjacency
matrix representation we use in the paper allows to highlight the existence of a quotient space structure in which each critical value of the loss function is represented only once, while all other critical points with the same critical value belong to the fiber associated to the quotient space. It also allows to easily determine stable and unstable submanifolds at the saddle points, even when the Hessian fails to obtain them.
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Image and Video Processing
Equivariant Denoisers for Plug and Play Image Restoration
Marien Renaud, Eliot Guez, Arthur Leclaire et al. (+1 more)
One key ingredient of image restoration is to define a realistic prior on clean images to complete the missing information in the observation. State-of-the-art restoration methods rely on a neural network to encode this prior. Typical image distributions are invariant to some set of transformations, such as rotations or flips. However, most deep architectures are not designed to represent an invariant image distribution. Recent works have proposed to overcome this difficulty by including equivariance properties within a Plug-and-Play paradigm. In this work, we propose two unified frameworks named Equivariant Regularization by Denoising (ERED) and Equivariant Plug-and-Play (EPnP) based on equivariant denoisers and
stochastic optimization. We analyze the convergence of the proposed
algorithms and discuss their practical benefit.
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All authors Marien Renaud, Eliot Guez, Arthur Leclaire, Nicolas Papadakis
Systems and Control
Security-Constrained AC/DC Grid Optimal Power Flow Considering Asymmetrical HVDC Grid Operation using Sparse Tableau Formulation
Oscar Damanik, Giacomo Bastianel, Dirk Van Hertem et al. (+1 more)
This paper presents a security-constrained optimal power flow (SCOPF) model for HVDC grids that optimizes the asymmetrical operation of bipolar converter stations, i.e., different current injections of the positive and negative converter poles, to minimize operational costs under post-contingency conditions caused by single converter pole outages. The optimization model allows the selection of the number of converter stations that operate asymmetrically. The results indicate that increasing the number of asymmetrical stations lowers operational costs. The analysis also provides insight into the sensitivity of these costs to the level of asymmetrical operation. However, increased asymmetrical operation leads to higher DC neutral voltage offsets that can rise to undesired levels. Imposing limits on these offsets can, in turn, increase operational costs. To mitigate these effects, a neutral line switching (NLS) strategy is proposed for the post-contingency state.
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All authors Oscar Damanik, Giacomo Bastianel, Dirk Van Hertem, Hakan Ergun
Signal Processing · Cross-listed from cs.IT
Reconfigurable Airspace: Synergizing Movable Antenna and Intelligent Surface for Low-Altitude ISAC Networks
Honghao Wang, Qingqing Wu, Yifan Jiang et al. (+7 more)
Low-altitude unmanned aerial vehicle (
UAV) networks are integral to future 6G integrated sensing and communication (
ISAC) systems. However, their deployment is hindered by challenges stemming from high mobility of
UAVs, complex propagation environments, and the inherent trade-offs between coexisting sensing and communication functions. This article proposes a novel framework that leverages movable
antennas (MAs) and intelligent reflecting surfaces (IRSs) as dual enablers to overcome these limitations. MAs, through active transceiver reconfiguration, and IRSs, via passive channel reconstruction, can work in synergy to significantly enhance system performance. Our analysis first elaborates on the fundamental gains offered by MAs and IRSs, and provides simulation results that validate the immense potential of the MA-IRS-enabled
ISAC architecture. Two core
UAV deployment scenarios are then investigated: (i)
UAVs as
ISAC users, where we focus on achieving high-precision tracking and aerial safety, and (ii)
UAVs as aerial network nodes, where we address robust design and complex coupled resource optimization. Finally, key technical challenges and research opportunities are identified and analyzed for each scenario, charting a clear course for the future design of advanced low-altitude
ISAC networks.
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All authors Honghao Wang, Qingqing Wu, Yifan Jiang, Ziyuan Zheng, Ziheng Zhang, Yanze Zhu, Ying Gao, Wen Chen, Guanghai Liu, Abbas Jamalipour
Signal Processing
Semantic Communication with Hopfield Memories
Karim Nasreddine, Christo Kurisummoottil Thomas and Walid Saad
Traditional joint source-channel coding employs static learned semantic representations that cannot dynamically adapt to evolving source distributions. Shared semantic
memories between transmitter and receiver can potentially enable bandwidth savings by reusing previously transmitted concepts as context to reconstruct data, but require effective mechanisms to determine when current content is similar enough to stored patterns. However, existing hard quantization approaches based on variational autoencoders are limited by frequent
memory updates even under small changes in data dynamics, which leads to inefficient usage of bandwidth.To address this challenge, in this paper, a
memory-augmented semantic communication framework is proposed where both transmitter and receiver maintain a shared
memory of semantic concepts using modern Hopfield networks (MHNs). The proposed framework employs soft
attention-based
retrieval that smoothly adjusts stored semantic prototype weights as data evolves that enables stable matching decisions under gradual data dynamics. A joint optimization of encoder, decoder, and
memory retrieval mechanism is performed with the objective of maximizing a
reasoning capacity metric that quantifies semantic efficiency as the product of
memory reuse rate and compression ratio. Theoretical analysis establishes the fundamental rate-distortion-reuse tradeoff and proves that soft
retrieval reduces unnecessary transmissions compared to hard quantization under bounded semantic drift. Extensive simulations over diverse
video scenarios demonstrate that the proposed MHN-based approach achieves substantial bit reductions around 14% on average and up to 70% in scenarios with gradual content changes compared to baseline.
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Systems and Control
Fault Detection in Solar Thermal Systems using Probabilistic Reconstructions
Florian Ebmeier, Nicole Ludwig, Jannik Thuemmel et al. (+2 more)
Solar thermal systems (STS) present a promising avenue for low-carbon heat generation, with a well-running system providing heat at minimal cost and carbon emissions. However, STS can exhibit faults due to improper installation, maintenance, or operation, often resulting in a substantial reduction in efficiency or even damage to the system. As monitoring at the individual level is economically prohibitive for small-scale systems, automated monitoring and fault detection should be used to address such issues. Recent advances in data-driven anomaly detection, particularly in time series analysis, offer a cost-effective solution by leveraging existing sensors to identify abnormal system states. Here, we propose a probabilistic reconstruction-based framework for anomaly detection. We evaluate our method on the publicly available PaSTS
dataset of operational domestic STS, which features real-world complexities and diverse fault types. Our experiments show that reconstruction-based methods can detect faults in domestic STS both qualitatively and quantitatively, while generalizing to previously unseen systems. We also demonstrate that our model outperforms both simple and more complex deep learning baselines. Additionally, we show that heteroscedastic uncertainty estimation is essential to fault detection performance. Finally, we discuss the engineering overhead required to unlock these improvements and make a case for simple deep learning models.
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All authors Florian Ebmeier, Nicole Ludwig, Jannik Thuemmel, Georg Martius, Volker H. Franz
Audio and Speech Processing
Music Flamingo: Scaling Music Understanding in Audio Language Models
Sreyan Ghosh, Arushi Goel, Lasha Koroshinadze et al. (+8 more)
We introduce Music Flamingo, a novel large audio-
language model designed to advance music (including song) understanding in foundational audio models. While audio-
language research has progressed rapidly, music remains challenging due to its dynamic, layered, and information-dense nature. Progress has been further limited by the difficulty of scaling open audio understanding models, primarily because of the scarcity of high-quality music data and annotations. As a result, prior models are restricted to producing short, high-level captions, answering only surface-level questions, and showing limited generalization across diverse musical cultures. To address these challenges, we curate MF-Skills, a large-scale
dataset labeled through a multi-stage pipeline that yields rich captions and question-answer pairs covering harmony, structure, timbre, lyrics, and cultural context. We fine-tune an enhanced Audio Flamingo 3 backbone on MF-Skills and further strengthen multiple skills relevant to music understanding. To improve the model's
reasoning abilities, we introduce a post-training recipe: we first cold-start with MF-Think, a novel chain-of-thought
dataset grounded in music theory, followed by GRPO-based reinforcement learning with custom rewards. Music Flamingo achieves state-of-the-art results across 10+
benchmarks for music understanding and
reasoning, establishing itself as a generalist and musically intelligent audio-
language model. Beyond strong empirical results, Music Flamingo sets a new standard for advanced music understanding by demonstrating how models can move from surface-level recognition toward layered, human-like perception of songs. We believe this work provides both a
benchmark and a foundation for the community to build the next generation of models that engage with music as meaningfully as humans do.
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All authors Sreyan Ghosh, Arushi Goel, Lasha Koroshinadze, Sang-gil Lee, Zhifeng Kong, Joao Felipe Santos, Ramani Duraiswami, Dinesh Manocha, Wei Ping, Mohammad Shoeybi, Bryan Catanzaro
Audio and Speech Processing · Cross-listed from cs.CL
MTR-DuplexBench: Towards a Comprehensive Evaluation of Multi-Round Conversations for Full-Duplex Speech Language Models
He Zhang, Wenqian Cui, Haoning Xu et al. (+5 more)
Full-Duplex
Speech Language Models (FD-SLMs) enable real-time, overlapping conversational interactions, offering a more dynamic user experience compared to traditional half-duplex models. However, existing
benchmarks primarily focus on evaluating single-round interactions, neglecting the complexities of multi-round communication. Evaluating FD-SLMs in multi-round settings poses significant challenges, including blurred turn boundaries in communication and context inconsistency during model inference. Also, existing
benchmarks often focus solely on evaluating conversational features, neglecting other critical aspects. To address these gaps, we introduce MTR-DuplexBench, a novel
benchmark designed for a comprehensive multi-round evaluation of FD-SLMs. MTR-DuplexBench not only segments continuous full-duplex dialogues into discrete turns for turn-by-turn assessment but also incorporates various evaluation aspects, including conversational features, dialogue quality, instruction following, and safety. Experimental results reveal that current FD-SLMs face difficulties in maintaining consistent performance across multiple rounds and evaluation dimensions, highlighting the necessity and effectiveness of our
benchmark. Code and data are available at: https://github.com/ZhangHe0918/MTR-DuplexBench
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All authors He Zhang, Wenqian Cui, Haoning Xu, Xiaohui Li, Lei Zhu, Haoli Bai, Shaohua Ma, Irwin King
Image and Video Processing · Cross-listed from cs.MM
Robustness and Imperceptibility Analysis of Hybrid Spatial-Frequency Domain Image Watermarking
Rizal Khoirul Anam
The proliferation of digital media necessitates robust methods for copyright protection and content authentication. This paper presents a comprehensive comparative study of digital image watermarking techniques implemented using the spatial domain (Least Significant Bit - LSB), the frequency domain (Discrete
Fourier Transform - DFT), and a novel hybrid (LSB+DFT) approach. The core objective is to evaluate the trade-offs between imperceptibility (measured by Peak Signal-to-Noise Ratio - PSNR) and robustness (measured by Normalized Correlation - NC and Bit Error Rate - BER). We implemented these three techniques within a unified MATLAB-based experimental framework. The watermarked images were subjected to a battery of common image processing attacks, including JPEG compression, Gaussian noise, and salt-and-pepper noise, at varying intensities. Experimental results generated from standard image
datasets (USC-SIPI) demonstrate that while LSB provides superior imperceptibility, it is extremely fragile. The DFT method offers significant robustness at the cost of visual quality. The proposed hybrid LSB+DFT technique, which leverages redundant
embedding and a fallback extraction mechanism, is shown to provide the optimal balance, maintaining high visual fidelity while exhibiting superior resilience to all tested attacks.
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Systems and Control
Generalized Intelligence for Tactical Decision-Making: Large Language Model-Driven Dynamic Weapon Target Assignment
Johannes Autenrieb and Ole Ostermann
Modern aerospace defense systems increasingly rely on autonomous decision-making to coordinate large numbers of interceptors against multiple incoming threats. Conventional weapon-target assignment (WTA)
algorithms, including mixed-integer programming and auction-based methods, show limitations in dynamic and uncertain tactical environments where human-like
reasoning and adaptive prioritization are required. This paper introduces a large
language model (LLM) driven WTA framework that integrates generalized intelligence into cooperative missile guidance. The proposed system formulates the tactical decision process as a
reasoning problem, in which an LLM evaluates spatial and temporal relationships among interceptors, targets, and defended assets to generate real-time assignments. In contrast to classical optimization methods, the approach leverages contextual mission data such as threat direction, asset priority, and closing velocity to adapt dynamically and reduce assignment switching. A dedicated simulation environment supports both static and dynamic assignment modes. Results demonstrate improved consistency, adaptability, and mission-level prioritization, establishing a foundation for integrating generalized artificial intelligence into tactical guidance systems.
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Signal Processing
High Order Delta-Sigma Modulation with Positive Integer Coefficients
Martin J. W. Schubert
This document proposes binomial integer parameters for the cascaded Delta-Sigma-modulator structure with distributed feedback and distributed feedforward input and multi-bit output. It is demonstrated that high orders can be achieved with these coefficients. Accuracy requirements concerning the coefficients are discussed.
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Signal Processing
NOMA-Enabled Dual-IRS Relay Network Integrated with Ambient Backscatter Communication
Chandrima Thakur, Priyanka Ghosh, Rashmita Badhai et al. (+1 more)
This paper analyzes a NOMA-enabled dual-Intelligent Reflecting Surface (IRS) relay network integrated with Ambient Backscatter (BS) communication. The system comprises a source, an energy-constrained relay with energy harvesting (EH) and BS capabilities, two NOMA users, and a BS node. The relay adopts a time-switching relaying (TSR) protocol to harvest energy and forward information ,while simultaneously enabling BS-based communication. Two IRS are deployed to enhance the S to R and R to (D1, D2) links under blockage conditions. Closed-form expressions for the Outage Probability (OP) and Throughput of both the main communication links and the BS-assisted secondary links are derived. Furthermore, throughput is analyzed under varying system parameters, including power allocation factors, reflection efficiency, IRS elements, and transmission rate. Monte Carlo simulations validate the analytical results. numerical findings reveal critical trade-offs between the main and RS links. The proposed framework provides useful insights for designing reliable and energy-efficient NOMA-IRS-aided BS networks for future IoT applications.
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All authors Chandrima Thakur, Priyanka Ghosh, Rashmita Badhai, Sumit Kundu
Systems and Control
Equivalent Mechanical Models for Sloshing
Francesco Capolupo
Propellant sloshing is a well-known, but not completely mastered phenomenon in space vehicles. It is particularly critical in both microgravity environments - such as interplanetary spacecraft requiring high pointing stability - and high-g conditions, as encountered during launch, re-entry, and landing. In both cases, sloshing can significantly affect vehicle performance and stability, and must often be explicitly considered in the design of the guidance,
navigation, and control (GNC) subsystem. For stability analysis and control design, the most common approach to modeling sloshing is through an equivalent mechanical representation, where the moving propellant is treated as a mechanical system interacting with the rigid (or flexible) spacecraft. Pendulum-based models and mass-spring-damper systems are widely used by control analysts to assess sloshing-induced perturbations on vehicles subjected to persistent non-gravitational acceleration along one of their body axes. In this work, we present a rigorous mathematical formulation of pendulum dynamics, starting from a single spherical pendulum attached to a rigid spacecraft. We derive the nonlinear equations of motion for this 8-degree-of-freedom multi-body system, and then extend the formulation to include multiple pendulums, representing multiple sloshing modes within a tank and/or multiple tanks on the same vehicle. Furthermore, we derive the corresponding linearized equations of motion, explicitly accounting for a nominal longitudinal force acting on the vehicle - consistent with the high-g sloshing regime - expressed in either the inertial or body frame. Finally, we demonstrate the mathematical equivalence between the pendulum and mass-spring-damper models and validate the proposed models through time-domain simulation and frequency-domain analysis.
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Audio and Speech Processing
Interpretable Binaural Deep Beamforming Guided by Time-Varying Relative Transfer Function
Ilai Zaidel and Sharon Gannot
In this work, we propose a deep beamforming framework for
speech enhancement in dynamic acoustic environments. The framework learns time-varying beamformer weights from noisy multichannel signals via a deep neural network, guided by a continuously tracked relative transfer function (RTF) of a moving target speaker. We analyze the network's spatial behavior on an 8-microphone linear array by evaluating narrowband and wideband beampatterns in three modes: (i) oracle guidance with true RTFs, (ii) guidance with subspace-tracked RTF estimates, and (iii) operation without RTF guidance. Results show that RTF guidance yields smoother, more spatially consistent beampatterns that track the target direction of arrival (DOA), whereas the unguided model fails to maintain a clear spatial focus. We further extend the framework to binaural beamforming for dynamic target-speaker enhancement. The system is trained using a head-related transfer function (HRTF)-based acoustic simulation of a moving source, enabling realistic spatial rendering at the left and right ears. Spatial cue preservation is quantitatively evaluated in terms of interaural level differences (ILD) and interaural time differences (ITD), demonstrating the method's suitability for hearable applications.
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Systems and Control
Closed Form Modelling and Identification of Banking Effects in Confined Waters
Jeppe H. Mikkelsen, Thomas T. Enevoldsen, Bugge T. Jensen et al. (+3 more)
Vessels navigating in confined waters are subject to banking effects, which are hydrodynamic forces and moments arising from pressure differentials between the vessel sides, significantly affecting manoeuvrability and safety. Existing numerical approaches such as computational fluid dynamics (CFD) can accurately capture these effects but are computationally expensive and unsuitable for real-time control or estimation. This paper presents a closed-form, first-principles model of banking effects. The model coefficients are identified using physics-informed regression on towing tank experiment data for a scaled container vessel. Validation through Shapley value analysis confirms the significance of the banking terms in reproducing the measured forces and moments. Lastly, the derived coefficients are shown to be non-dimensional, making the model applicable across different scales that preserve vessel geometry.
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All authors Jeppe H. Mikkelsen, Thomas T. Enevoldsen, Bugge T. Jensen, Michael Jeppesen, Roberto Galeazzi, Dimitrios Papageorgiou
Systems and Control
Consensus approximation and impulsive control for a class of uncertain multi-agent dynamics
Zoltan Nagy, Irinel-Constantin Morarescu and Lucian Busoniu
This paper studies a class of consensus dynamics where the interactions between
agents are affected by a time-varying unknown scaling factor. This situation is encountered in the control of robotic fleets over a wireless network or in opinion dynamics where the confidence given to the peers varies in time. Firstly, we establish conditions under which practical upper and lower bounds on the consensus value can be determined. Secondly, we propose control strategies for allocating a given control budget to shift
agent states towards a desired consensus value despite the uncertainty. We provide computationally efficient linear programming-based approaches for both problems and validate the obtained results in numerical simulations.
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Systems and Control
Cooperative Control of Hybrid FES-Exoskeleton: Dynamic Allocation
Hossein Kavianirad, Satoshi Endo, Davide Astarita et al. (+3 more)
Hybrid assistive systems that integrate functional electrical stimulation (FES) and robotic exoskeletons offer a promising approach for neurorehabilitation. However, control of these systems remains challenging due to actuator redundancy and heterogeneous assistive device constraints. This paper introduces a novel cooperative control architecture based on dynamic allocation to address actuator redundancy in a hybrid FES-exoskeleton system. The proposed approach employs a modular control allocator that redistributes required control torques between FES and exoskeleton actuators in real time, accounting for device-specific limitations and user preferences (e.g., prioritizing one assistive device over another). Within this framework, the high-level controller determines the total assistance level, while the allocator dynamically distributes control effort based on these assistive device-specific considerations. Simulation results and experimental validation demonstrate the method's effectiveness in resolving actuator redundancy in the FES-exoskeleton system while reflecting actuator constraints, indicating its potential for deployment in clinical studies to assess patient acceptance and clinical efficacy.
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All authors Hossein Kavianirad, Satoshi Endo, Davide Astarita, Lorenzo Amato, Emilio Trigili, Sandra Hirche
Systems and Control · Cross-listed from cs.CV
VLF-MSC: Vision-Language Feature-Based Multimodal Semantic Communication System
Gwangyeon Ahn, Jiwan Seo and Joonhyuk Kang
We propose
Vision-
Language Feature-based
Multimodal Semantic Communication (VLF-MSC), a unified system that transmits a single compact
vision-
language representation to support both image and text generation at the receiver. Unlike existing semantic communication techniques that process each modality separately, VLF-MSC employs a pre-trained
vision-
language model (VLM) to encode the source image into a
vision-
language semantic feature (VLF), which is transmitted over the wireless channel. At the receiver, a decoder-based
language model and a
diffusion-based image generator are both conditioned on the VLF to produce a descriptive text and a semantically aligned image. This unified representation eliminates the need for modality-specific streams or retransmissions, improving spectral efficiency and adaptability. By leveraging foundation models, the system achieves robustness to channel noise while preserving semantic fidelity. Experiments demonstrate that VLF-MSC outperforms text-only and image-only baselines, achieving higher semantic accuracy for both modalities under low SNR with significantly reduced bandwidth.
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Signal Processing
Bridging the Initialization Gap: A Co-Optimization Framework for Mixed-Size Global Placement
Yuhao Ren, Yiting Liu, Yanfei Zhou et al. (+4 more)
Global placement is a critical step with high computational complexity in VLSI physical design. Modern analytical placers formulate the placement problem as a nonlinear optimization, where initialization strongly affects both convergence behavior and final placement quality. However, existing initialization methods exhibit a trade-off: area-aware initializers account for
cell areas but are computationally expensive and can dominate total runtime, while fast point-based initializers ignore
cell area, leading to a modeling gap that impairs convergence and solution quality. We propose a lightweight co-optimization framework that bridges this initialization gap through two strategies. First, an area-hint refinement initializer incorporates heuristic
cell area information into a signed graph signal by augmenting the netlist graph with virtual nodes and negative-weight edges, yielding an area-aware and spectrally smooth placement initialization. Second, a macro-schedule placement procedure progressively restores area constraints, enabling a smooth transition from the refined initializer to the full area-aware objective and producing high-quality placement results. We evaluate the framework on macro-heavy ISPD2005 academic
benchmarks and two real-world industrial designs across two technology nodes (12 cases in total). Experimental results show that our method consistently improves half-perimeter wirelength (HPWL) over point-based initializers in 11 out of 12 cases, achieving up to 2.2% HPWL reduction, while running approximately 100 times faster than the state-of-the-art area-aware initializer.
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All authors Yuhao Ren, Yiting Liu, Yanfei Zhou, Zhiyu Zheng, Li Shang, Fan Yang, Zhiang Wang