Systems and Control
From Big Data to Fast Data: Towards High-Quality Datasets for Machine Learning Applications from Closed-Loop Data Collection
Philipp Reis, Jacqueline Henle, Stefan Otten et al. (+1 more)
The increasing capabilities of machine learning models, such as
vision-
language and
multimodal language models, are placing growing demands on data in automotive systems engineering, making the quality and relevance of collected data enablers for the development and validation of such systems. Traditional Big Data approaches focus on large-scale data collection and offline processing, while Smart Data approaches improve data selection strategies but still rely on centralized and offline post-processing. This paper introduces the concept of Fast Data for automotive systems engineering. The approach shifts data selection and recording onto the vehicle as the data source. By enabling real-time, context-aware decisions on whether and which data should be recorded, data collection can be directly aligned with data quality objectives and collection strategies within a closed-loop. This results in
datasets with higher relevance, improved coverage of critical scenarios, and increased information density, while at the same time reducing irrelevant data and associated costs. The proposed approach provides a structured foundation for designing data collection strategies that are aligned with the needs of modern machine learning
algorithms. It supports efficient data acquisition and contributes to scalable and cost-effective ML development processes in automotive systems engineering.
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All authors Philipp Reis, Jacqueline Henle, Stefan Otten, Eric Sax
Signal Processing
SCROOGE: A Physics-Aware Framework for Efficient Orchestration of RIS-Assisted Networks
Alexandros I. Papadopoulos, Sotiris Kopsinos, Dimitrios Tyrovolas et al. (+4 more)
Reconfigurable Intelligent Surfaces (RISs) are emerging as a key enabler of Programmable Wireless Environments for 6G, but their practical integration into operational networks still lacks orchestration mechanisms that can jointly support resource allocation, energy efficiency, and admission control with low online complexity. This paper presents SCROOGE, a physics-aware orchestration framework for multi-user RIS-assisted networks that operates on information generated offline during RIS codebook compilation, namely optimal codebook entries and per-element influence scores. Rather than relying on online optimization or idealized fading-based abstractions, SCROOGE exploits physics-derived descriptors to support low-latency operating-phase decisions that remain compatible with network-level control requirements. Specifically, SCROOGE introduces: i) an influence-aware, tier-consistent resource-allocation mechanism that combines user priority and element importance in the construction of a common RIS configuration; ii) an energy-efficiency mechanism that deactivates globally low-influence elements; and iii) an admission-control mechanism that accepts or rejects candidate users based on tier-aware compatibility with the currently deployed RIS state.
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All authors Alexandros I. Papadopoulos, Sotiris Kopsinos, Dimitrios Tyrovolas, Antonios Lalas, Konstantinos Votis, George K. Karagiannidis, Christos Liaskos
Systems and Control
Dual MPC for quasi-Linear Parameter Varying systems
Sampath Kumar Mulagaleti and Alberto Bemporad
We present a dual Model Predictive Control (MPC) framework for the simultaneous identification and control of quasi-Linear Parameter Varying (qLPV) systems. The framework is composed of an online
estimator for the states and parameters of the qLPV system, and a controller that leverages the estimated model to compute inputs with a dual purpose: tracking a reference output while actively exciting the system to enhance parameter estimation. The core of this approach is a robust tube-based MPC scheme that exploits recent developments in polytopic geometry to guarantee recursive feasibility and stability in spite of model uncertainty. The effectiveness of the framework in achieving improved tracking performance while identifying a model of the system is demonstrated through a numerical example.
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Image and Video Processing
Polyhedral Unmixing: Bridging Semantic Segmentation with Hyperspectral Unmixing via Polyhedral-Cone Partitioning
Antoine Bottenmuller, Etienne Decencière and Petr Dokládal
Semantic
segmentation and hyperspectral unmixing are two central problems in spectral image analysis. The former assigns each pixel a discrete label corresponding to its material class, whereas the latter estimates pure material spectra, called endmembers, and, for each pixel, a vector representing material abundances in the observed scene. Despite their complementarity, these two problems are usually addressed independently. This paper aims to bridge these two lines of work by formally showing that, under the linear mixing model, pixel classification by dominant materials induces polyhedral-cone regions in the spectral space. We leverage this fundamental property to propose a direct
segmentation-to-unmixing pipeline that performs blind hyperspectral unmixing from any semantic
segmentation by constructing a polyhedral-cone partition of the space that best fits the labeled pixels. Signed distances from pixels to the estimated regions are then computed, linearly transformed via a change of basis in the distance space, and projected onto the probability simplex, yielding an initial abundance estimate. This estimate is used to extract endmembers and recover final abundances via
matrix pseudo-inversion. Because the
segmentation method can be freely chosen, the user gains explicit control over the unmixing process, while the rest of the pipeline remains essentially deterministic and lightweight. Beyond improving interpretability, experiments on three real
datasets demonstrate the effectiveness of the proposed approach when associated with appropriate clustering
algorithms, and show consistent improvements over recent deep and non-deep state-of-the-art methods. The code is available at: https://github.com/antoine-bottenmuller/polyhedral-unmixing
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Signal Processing · Cross-listed from cs.LG
mtslearn: Machine Learning in Python for Medical Time Series
Zhongheng Jiang, Yuechao Zhao, Donglin Xie et al. (+5 more)
Medical time-series data captures the dynamic progression of patient conditions, playing a vital role in modern clinical decision support systems. However, real-world clinical data is highly heterogeneous and inconsistently formatted. Furthermore, existing machine learning tools often have steep learning curves and fragmented workflows. Consequently, a significant gap remains between cutting-edge AI technologies and clinical application. To address this, we introduce mtslearn, an end-to-end integrated toolkit specifically designed for medical time-series data. First, the framework provides a unified data interface that automates the parsing and
alignment of wide, long, and flat data formats. This design significantly reduces data cleaning overhead. Building on this, mtslearn provides a complete pipeline from data reading and feature engineering to model training and result visualization. Furthermore, it offers flexible interfaces for custom
algorithms. Through a modular design, mtslearn simplifies complex data engineering tasks into a few lines of code. This significantly lowers the barrier to entry for clinicians with limited programming experience, empowering them to focus more on exploring medical hypotheses and accelerating the translation of advanced
algorithms into real-world clinical practice. mtslearn is publicly available at https://github.com/PKUDigitalHealth/mtslearn.
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All authors Zhongheng Jiang, Yuechao Zhao, Donglin Xie, Chenxi Sun, Rongchen Lu, Silu Luo, Zisheng Liang, Shenda Hong
Image and Video Processing
Rich-U-Net: A medical image segmentation model for fusing spatial depth features and capturing minute structural details
Zhuoyi Fang, Kexuan Shi, Jiajia Liu et al. (+1 more)
Medical image
segmentation is of great significance in analysis of illness. The use of deep neural networks in medical image
segmentation can help doctors extract regions of interest from complex medical images, thereby improving diagnostic accuracy and enabling better assessment of the condition to formulate treatment plans. However, most current medical image
segmentation methods underperform in accurately extracting spatial information from medical images and mining potential complex structures and variations. In this article, we introduce the Rich-U-Net model, which effectively integrates both spatial and depth features. This fusion enhances the model's capability to detect fine structures and intricate details within complex medical images. Our multi-level and multi-dimensional feature fusion and optimization strategies enable our model to achieve fine structure localization and accurate
segmentation results in medical image
segmentation. Experiments on the ISIC2018, BUSI, GLAS, and CVC
datasets show that Rich-U-Net surpasses other state-of-the-art models in Dice, IoU, and HD95 metrics.
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All authors Zhuoyi Fang, Kexuan Shi, Jiajia Liu, Qiang Han
Signal Processing · Cross-listed from physics.optics
Model-Based Beam-Steered Optical Wireless Positioning with Single-LED Single-Photodiode for 3D Localization
Kevin Acuna-Condori, Bastien Béchadergue, Hongyu Guan et al. (+1 more)
State-of-the-art optical wireless positioning (OWP) commonly reaches centimeter-level accuracy by depending on dense multi-light-emitting diodes (LED) infrastructures, photodiode (PD) arrays, or image-sensor receivers, incurring hardware complexity and deployment cost. This paper introduces a single beam-steered LED, single-PD OWP architecture that achieves three-dimensional (3D) localization without receiver rotation, cameras, or PD arrays; the core idea is to steer the transmitter through K known orientations and exploit the resulting received-signal-strength variations at the PD to estimate LED-to-PD direction and distance. We derive a composite Cramer-Rao lower bound and position-error bound (PEB) for the joint observation model, and cast the steering-pattern design as a genetic
algorithm that minimizes the PEB over a 3D testbed. We develop both model-based a constrained nonlinear
estimator and closed-form direction
estimators: a statistically efficient generalized least squares solution, and a lightweight weighted least squares approximation. Simulations demonstrate centimeter-level accuracy for 3D OWP with a single beam-steered LED and a single PD.
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All authors Kevin Acuna-Condori, Bastien Béchadergue, Hongyu Guan, Luc Chassagne
Systems and Control
Communication-Aware Synthesis of Safety Controller for Networked Control Systems
Yihan Liu, Meiqi Tian, Teng Yan et al. (+1 more)
This paper studies communication-aware safe control for discrete-time linear multi-
agent systems under limited information exchange. The main challenge lies in the coupling between remote-state estimation and safe controller design, since estimation errors affect the state
evolution through the controller gains, while the controller design must account for the resulting observer-induced state perturbations to guarantee safety. To address this challenge, a distributed input predictor is incorporated into a $k$-hop state observer to reconstruct unavailable remote states, and the resulting estimation errors are characterized to quantify the observer-induced state perturbations. An overall robust safety invariant (RSI) set is then constructed by jointly accounting for individual
agent state constraints and prescribed safety constraints on the relative states of interacting
agents under these perturbations. A linear
matrix inequality (LMI)-based optimization method is developed to jointly synthesize the distributed observers, local controllers, and the RSI set. A case study illustrates the effectiveness of the proposed method.
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All authors Yihan Liu, Meiqi Tian, Teng Yan, Bingzhuo Zhong
Signal Processing
A Three-Dimensional Path Loss Model for THz Band Aerial Communications
Sina Jorjani, Caglar Tunc, Ozgur Gurbuz et al. (+1 more)
Accurate characterization of Terahertz (THz) band path loss is critical for reliable high-frequency communication, especially in aerial networks where transceivers may operate at different altitudes. Existing THz-band path loss models for aerial networks focus on horizontal or vertical transceiver deployments, and fall short at modeling the random 3D geometry of transceiver locations. To address this limitation, we propose a new analytical THz path loss model that incorporates arbitrary 3D geometry of transceiver locations and frequency-selective absorption, obtained through a two-dimensional regression. We validate our proposed model with the propagation data collected via the Atmospheric Model (am) tool for multiple aerial link types, including drone-to-drone (Dr2Dr), medium-altitude aerial communication (MAAC), high-altitude unmanned aerial vehicles~(
UAV)-to-
UAV (U2U) links over varying transceiver separation and sub-THz to low-THz spectrum, i.e., 0.1–1~THz. The proposed framework provides a unified and accurate model for analyzing and designing future high-frequency aerial communication systems.
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All authors Sina Jorjani, Caglar Tunc, Ozgur Gurbuz, Akhtar Saeed
Signal Processing
Intelligent Forensics in Next-Generation Mobile Networks: Evidence, Methods, and Applications
Jiacheng Wang, Weihong Qin, Jialing He et al. (+3 more)
This survey examines intelligent forensics in next-generation mobile networks, arguing that future wireless security must move beyond real-time detection toward accountable post-incident reconstruction. Unlike traditional digital forensics, wireless investigations rely on short-lived, distributed, and heterogeneous evidence, including
radio waveforms, channel measurements, device-side artifacts, and network telemetry, affected by calibration, timing uncertainty,
privacy constraints, and
adversarial manipulation. To address this limitation, this paper develops an evidence-centric framework that treats wireless measurements as first-class forensic artifacts and organizes the field through a unified taxonomy spanning physical-layer, device-layer, network-layer, and cross-layer forensics. We further systematize the forensic workflow into readiness and preservation-by-design, acquisition, correlation and analysis, and reporting and reproducibility, while comparing the complementary roles of traditional methods and artificial intelligence-assisted techniques. Subsequently, we review major application areas, including anomaly discovery, attribution, provenance and localization, authenticity verification, and timeline reconstruction. Finally, we identify key open challenges, including domain shift, resource-aware evidence capture, and the benefits and admissibility risks of generative evidence. Overall, this paper positions wireless forensics as a foundational capability for trustworthy, auditable, and reproducible security in next-generation wireless systems. Readers can understand and streamline wireless forensics processes for specific applications, such as low-altitude wireless networks, vehicular communications, and edge general intelligence.
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All authors Jiacheng Wang, Weihong Qin, Jialing He, Changyuan Zhao, Dusit Niyato, Tao Xiang
Signal Processing
Space-Time Adaptive Beamforming for Satellite Communications: Harnessing Doppler as New Signaling Dimensions
Hyeongtak Yun, Seyong Kim and Jeonghun Park
Low Earth orbit (LEO) satellite downlinks are fundamentally limited by severe channel correlation: the line-of-sight (LoS)-dominant propagation and high orbital altitude confine users to a narrow angular region, rendering the multiuser channel
matrix ill-conditioned. This paper provides a rigorous characterization of this limitation by exploiting the Vandermonde structure of the channel. Specifically, we link the minimum
eigenvalue of the channel Gram
matrix to user crowding through a balls-and-bins abstraction, and derive asymptotic sum rate scaling laws for both uniform linear arrays and uniform planar arrays. Our analysis reveals a sharp density threshold beyond which zero-forcing (ZF) precoding provably fails. To overcome this spatial multiplexing breakdown, we propose space-time adaptive beamforming (STAB), which exploits user-dependent residual Doppler shifts as an additional discrimination dimension. By constructing a time-extended channel in the joint space-Doppler domain, STAB restores a non-vanishing sum rate in regimes where purely spatial ZF collapses, {with a matching achievability bound.} We further develop a space-Doppler user selection (SDS)
algorithm that leverages both spatial and Doppler separability for scheduling. Numerical results corroborate the analytical predictions and demonstrate that the combination of STAB and SDS achieves substantial sum rate gains over conventional methods in realistic dense LEO downlink scenarios.
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Signal Processing
ARC: Alignment-based RPM Estimation with Curvature-adaptive Tracking
Weiheng Hua and Changyu Hao
Tacho-less rotational speed estimation is critical for vibration-based prognostics and health management (PHM) of rotating machinery, yet traditional methods–such as time-domain periodicity, cepstrum, and harmonic comb matching–struggle under noise, non-stationarity, and inharmonic interference. Probabilistic tracking offers a principled way to fuse multiple
estimators, but a major challenge is that heterogeneous
estimators produce evidence on incompatible axes and scales. We address this with ARC (
Alignment-based RPM Estimation with
Curvature-adaptive Tracking) by unifying the observation representation. Each
estimator outputs a one-dimensional evidence curve on its native axis, which is mapped onto a shared RPM grid and converted into a comparable grid-based log-likelihood via robust standardization and a Gibbs-form energy shaping. Standard recursive filtering with fixed-variance motion priors can fail under multi-modal or ambiguous evidence. To overcome this, ARC introduces a
curvature-informed, state-dependent motion prior, where the transition variance is derived from the local discrete Hessian of the previous log-posterior. This design enforces smooth tracking around confident modes while preserving competing hypotheses, such as octave alternatives. Experiments on synthetic stress tests and real vibration-table data demonstrate stable, physically plausible trajectories with interpretable uncertainty, and ablations confirm that these gains arise from uncertainty-aware temporal propagation rather than per-frame peak selection or ad hoc rules.
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Signal Processing
Accelerating 5G Synchronization Signal Timing Offset Estimation Using Dual-Rate Sampling
Bitna Kim, Seungyeon Lee, Yelan Lee et al. (+1 more)
Cell search engineers face significant challenge in reducing computation time to meet the requirements for fast initial access and
radio link recovery. Since the majority of
cell search time is consumed by Primary Synchronization Signal (PSS) detection, reducing the computational burden of this step is critical for shortening the overall procedure. This paper proposes a novel timing offset estimation scheme designed to accelerate 5G
cell search. Leveraging the 5G Synchronization Signal Block (SSB) structure, the proposed scheme employs a two-step estimation process using dual-rate sampling. This approach effectively reduces the PSS detection search space without compromising the performance of subsequent processes. Performance evaluations in practical system and channel environments demonstrate that the proposed scheme reduces the
cell search procedure time by 68% compared to the baseline, while maintaining Physical Broadcast CHannel (PBCH) decoding performance.
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All authors Bitna Kim, Seungyeon Lee, Yelan Lee, Juyeop Kim
Audio and Speech Processing · Cross-listed from cs.SD
LongCat-AudioDiT: High-Fidelity Diffusion Text-to-Speech in the Waveform Latent Space
Detai Xin, Shujie Hu, Chengzuo Yang et al. (+4 more)
We present LongCat-AudioDiT, a novel, non-autoregressive
diffusion-based text-to-
speech (TTS) model that achieves state-of-the-art (SOTA) performance. Unlike previous methods that rely on intermediate acoustic representations such as mel-spectrograms, the core innovation of LongCat-AudioDiT lies in operating directly within the waveform latent space. This approach effectively mitigates compounding errors and drastically simplifies the TTS pipeline, requiring only a waveform variational autoencoder (Wav-VAE) and a
diffusion backbone. Furthermore, we introduce two critical improvements to the inference process: first, we identify and rectify a long-standing training-inference mismatch; second, we replace traditional classifier-free guidance with adaptive projection guidance to elevate generation quality. Experimental results demonstrate that, despite the absence of complex multi-stage training pipelines or high-quality human-annotated
datasets, LongCat-AudioDiT achieves SOTA zero-shot voice cloning performance on the Seed
benchmark while maintaining competitive intelligibility. Specifically, our largest variant, LongCat-AudioDiT-3.5B, outperforms the previous SOTA model (Seed-TTS), improving the speaker similarity (SIM) scores from 0.809 to 0.818 on Seed-ZH, and from 0.776 to 0.797 on Seed-Hard. Finally, through comprehensive ablation studies and systematic analysis, we validate the effectiveness of our proposed modules. Notably, we investigate the interplay between the Wav-VAE and the TTS backbone, revealing the counterintuitive finding that superior reconstruction fidelity in the Wav-VAE does not necessarily lead to better overall TTS performance. Code and model weights are released to foster further research within the
speech community.
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All authors Detai Xin, Shujie Hu, Chengzuo Yang, Chen Huang, Guoqiao Yu, Guanglu Wan, Xunliang Cai
Signal Processing
Semantic Communication for 6G Networks: A Trade-off between Distortion Criticality and Information Representability
Faizan Shafi, Rahul Jashvantbhai Pandya, Christo Kurisummoottil Thomas et al. (+1 more)
In this work, a self-
attention based conditional generative
adversarial network (SA-cGAN) framework for the sixth generation (6G) semantic communication system is proposed, explicitly designed to balance the trade-off between distortion criticality and information representability under varying channel conditions. The proposed SA-cGAN model continuously learns compact semantic representations by jointly considering semantic importance, reconstruction distortion, and channel quality, enabling adaptive selection of semantic
tokens for transmission. A knowledge graph is integrated to preserve contextual relationships and enhance semantic robustness, particularly in low signal-to-noise ratio (SNR) regimes. The resulting optimization framework incorporates continuous relaxation, submodular semantic selection, and principled constraint handling, allowing efficient semantic resource allocation under bandwidth and multi-constraint conditions. Simulation results show that, although SA-cGAN achieves modest syntactic bilingual evaluation understudy scores at low SNR to approximately 0.72 at 20 dB, it significantly outperforms conventional and JSCC-based schemes in semantic metrics, with semantic similarity, semantic accuracy, and semantic completeness consistently improving above 0.90 with SNR. Additionally, the model exhibits adaptive compression behavior, aggressively reducing redundant content while preserving critical semantic information to maintain fidelity. The convergence of training loss further validates stable and efficient learning of semantic representations. Overall, the results confirm that the proposed SA-cGAN model effectively captures distortion-invariant semantic representations and dynamically adapts transmitted content based on distortion criticality and information representability for meaning-centric communication in future 6G networks.
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All authors Faizan Shafi, Rahul Jashvantbhai Pandya, Christo Kurisummoottil Thomas, Sridhar Iyer
Systems and Control
Receding-Horizon Policy Gradient for Polytopic Controller Synthesis
Shiva Shakeri, Péter Baranyi and Mehran Mesbahi
We propose the Polytopic Receding-Horizon Policy Gradient (P-RHPG)
algorithm for synthesizing Parallel Distributed Compensation (PDC) controllers via Tensor Product (TP) model transformation. Standard LMI-based PDC synthesis grows increasingly conservative as model fidelity improves; P-RHPG instead solves a finite-horizon integrated cost via backward-stage decomposition. The key result is that each stage subproblem is a strongly convex quadratic in the vertex gains, a consequence of the linear independence of the HOSVD weighting functions, guaranteeing a unique global minimizer and linear convergence of gradient descent from any initialization. With zero terminal cost, the optimal cost increases monotonically to a finite limit and the gain sequence remains bounded; terminal costs satisfying a mild Lyapunov condition yield non-increasing convergence. Experiments on an aeroelastic wing
benchmark confirm convergence to a unique infinite-horizon optimum across all tested terminal cost choices and near-optimal performance relative to the pointwise Riccati lower bound.
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Systems and Control
Bilevel MPC for Linear Systems: A Tractable Reduction and Continuous Connection to Hierarchical MPC
Ryuta Moriyasu, Carmen Amo Alonso and Marco Pavone
Model predictive control (MPC) has been widely used in many fields, often in hierarchical architectures that combine controllers and decision-making layers at different levels. However, when such architectures are cast as bilevel optimization problems, standard KKT-based reformulations often introduce nonconvex and potentially nonsmooth structures that are undesirable for real-time verifiable control. In this paper, we study a bilevel MPC architecture composed of (i) an upper layer that selects the reference sequence and (ii) a lower-level linear MPC that tracks such reference sequence. We propose a smooth single-level reduction that does not degrade performance under a verifiable block-
matrix nonsingularity condition. In addition, when the problem is convex, its solution is unique and equivalent to a corresponding centralized MPC, enabling the inheritance of closed-loop properties. We further show that bilevel MPC is a natural extension of standard hierarchical MPC, and introduce an interpolation framework that continuously connects the two via move-blocking. This framework reveals optimal-value ordering among the resulting formulations and provides inexpensive a posteriori degradation certificates, thereby enabling a principled performance-computational efficiency trade-off.
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Systems and Control
Real-Time Surrogate Modeling for Fast Transient Prediction in Inverter-Based Microgrids Using CNN and LightGBM
Osasumwen Cedric Ogiesoba-Eguakun, Kaveh Ashenayi and Suman Rath
Real-time monitoring of inverter-based microgrids is essential for stability, fault response, and operational decision-making. However, electromagnetic transient (EMT) simulations, required to capture fast inverter dynamics, are computationally intensive and unsuitable for real-time applications. This paper presents a data-driven surrogate modeling framework for fast prediction of microgrid behavior using convolutional neural networks (CNN) and Light Gradient Boosting Machine (LightGBM). The models are trained on a high-fidelity EMT digital twin
dataset of a microgrid with ten distributed generators under eleven operating and disturbance scenarios, including faults, noise, and communication delays. A sliding-window method is applied to predict important system variables, including voltage magnitude, frequency, total active power, and voltage dip. The results show that model performance changes depending on the type of variable being predicted. The CNN demonstrates high accuracy for time-dependent signals such as voltage, with an $R^2$ value of 0.84, whereas LightGBM shows better performance for structured and disturbance-related variables, achieving an $R^2$ of 0.999 for frequency and 0.75 for voltage dip. A combined CNN+LightGBM model delivers stable performance across all variables. Beyond accuracy, the surrogate models also provide major improvements in computational efficiency. LightGBM achieves more than $1000\times$ speedup and runs faster than real time, while the hybrid model achieves over $500\times$ speedup with near real-time performance. These findings show that data-driven surrogate models can effectively represent microgrid dynamics. They also support real-time and faster-than-real-time predictions. As a result, they are well-suited for applications such as monitoring, fault analysis, and control in inverter-based power systems.
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Systems and Control · Cross-listed from math.OC
Pointwise and dynamic programming control synthesis for finite-level open quantum memory systems
Igor G. Vladimirov, Ian R. Petersen and Guodong Shi
This paper is concerned with finite-level
quantum memory systems for retaining initial dynamic variables in the presence of external
quantum noise. The system variables have an algebraic structure, similar to that of the Pauli
matrices, and their Heisenberg picture
evolution is governed by a quasilinear
quantum stochastic differential equation. The latter involves a
Hamiltonian whose parameters depend affinely on a classical control signal in the form of a deterministic function of time. The
memory performance is quantified by a mean-square deviation of
quantum system variables of interest from their initial conditions. We relate this functional to a
matrix-valued state of an auxiliary classical control-affine dynamical system. This leads to a pointwise control design where the control signal minimises the time-derivative of the mean-square deviation with an additional quadratic penalty on the control. In an alternative finite-horizon setting with a terminal-integral cost functional, we apply dynamic programming and obtain a quadratically nonlinear Hamilton-Jacobi-Bellman equation, for which a solution is outlined in the form of a recursively computed asymptotic expansion.
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Signal Processing
A Novel Low-Complexity Dual-Domain Expectation Propagation Detection Aided AFDM for Future Communications
Qin Yi, Ping Yang, Zilong Liu et al. (+3 more)
This paper presents a dual-domain low-complexity expectation propagation (EP) detection framework for affine frequency division multiplexing (AFDM) systems. By analyzing the structural properties of the effective channel
matrices in both the time and affine frequency (AF) domains, our key observation is the domain-specific quasi-banded sparsity patterns, including AF-domain sparsity under frequency-selective channels and time-domain sparsity under doubly-selective channels. Based on these observations, we develop an AF-domain EP (EP-AF) detector for frequency-selective channels and a time-domain EP (EP-T) detector for doubly-selective channels, respectively. By performing iterative inference in the time domain using the Gaussian approximation, the proposed EP-T detector avoids inverting the dense channel
matrix in the AF domain. Furthermore, the proposed EP-AF and EP-T detectors leverage the aforementioned quasi-banded sparsity of the AF domain and time domain channel
matrices, respectively, to reduce the complexity of
matrix inversion from cubic to linear order. Simulation results demonstrate that the proposed low-complexity EP-AF detector achieves nearly identical error rate performance to its conventional counterpart, while the proposed low-complexity EP-T detector offers an attractive trade-off between detection performance and complexity.
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All authors Qin Yi, Ping Yang, Zilong Liu, Zeping Sui, Yue Xiao, Gang Wu
Audio and Speech Processing
Advancing LLM-based phoneme-to-grapheme for multilingual speech recognition
Lukuan Dong, Ziwei Li, Saierdaer Yusuyin et al. (+2 more)
Phoneme-based ASR factorizes recognition into
speech-to-phoneme (S2P) and phoneme-to-grapheme (P2G), enabling cross-lingual acoustic sharing while keeping
language-specific orthography in a separate module. While large
language models (LLMs) are promising for P2G,
multilingual P2G remains challenging due to
language-aware generation and severe cross-
language data imbalance. We study
multilingual LLM-based P2G on the ten-
language CV-Lang10
benchmark. We examine robustness strategies that account for S2P uncertainty, including DANP and Simplified SKM (S-SKM). S-SKM is a Monte Carlo approximation that avoids CTC-based S2P probability weighting in P2G training. Robust training and low-resource oversampling reduce the average WER from 10.56% to 7.66%.
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All authors Lukuan Dong, Ziwei Li, Saierdaer Yusuyin, Xianyu Zhao, Zhijian Ou
Systems and Control
A Continuous-Time and State-Space Relaxation of the Linear Threshold Model with Nonlinear Opinion Dynamics
Ian Xul Belaustegui, Himani Sinhmar, Ling-Wei Kong et al. (+2 more)
The Linear Threshold Model (LTM) is widely used to study the propagation of collective behaviors as complex contagions. However, its dependence on discrete states and timesteps restricts its ability to capture the multiple time-scales inherent in decision-making, as well as the effects of subthreshold signaling. To address these limitations, we introduce a continuous-time and state-space relaxation of the LTM based on the Nonlinear Opinion Dynamics (NOD) framework. By replacing the discontinuous step-function thresholds of the LTM with the smooth bifurcations of the NOD model, we map discrete cascade processes to the continuous flow of a dynamical system. We prove that, under appropriate parameter choices, activation in the discrete LTM guarantees activation in the continuous NOD relaxation for any given seed set. We establish computable conditions for equivalence: by sufficiently bounding the social coupling parameter, the continuous NOD cascades exactly recover the cascades of the discrete LTM. We then illustrate how this NOD relaxation provides a richer analytical framework than the LTM, allowing for the exploration of cascades driven by strictly subthreshold inputs and the role of temporally distributed signals.
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All authors Ian Xul Belaustegui, Himani Sinhmar, Ling-Wei Kong, Andrew Michael Hein, Naomi Ehrich Leonard
Image and Video Processing
Retinal Malady Classification using AI: A novel ViT-SVM combination architecture
Shashwat Jha, Vishvaditya Luhach and Raju Poddar
Macular Holes, Central serous retinopathy and Diabetic Retinopathy are one of the most widespread maladies of the eyes responsible for either partial or complete
vision loss, thus making it clear that early detection of the mentioned defects is detrimental for the well-being of the patient. This study intends to introduce the application of
Vision Transformer and Support Vector Machine based hybrid architecture (ViT-SVM) and analyse its performance to classify the optical coherence topography (OCT) Scans with the intention to automate the early detection of these retinal defects.
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Signal Processing
Indian Peak Power demand Forecasting : Transformer Based Implementation of Temporal Architecture
Vishvaditya Luhach and Shashwat Jha
The long-term
forecasting of electricity demand has been a prevalent research topic, primarily because of its economic and strategic relevance. Several machine learning as well as deep learning techniques have been developed in parallel with the growing complexity of the peak demand, planning for generation facilities and transmission augmentation in future. Most of these proposed techniques work on short-term
forecasting as long-term
forecasting is considerably more challenging due to unpredictable and unforeseeable variables that may arise in the future. This paper proposes a Temporal Fusion
Transformer based deep learning approach for long term
forecasting of peak power demand. The
dataset used in this paper consists of peak power demand in India for a period of 6 years and the prediction was done for a period of 1 year. Our proposed model was compared with other popular
forecasting models and it performed considerably better in
benchmarks and was also more accurate in modelling the variance in the power demand.
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Signal Processing · Cross-listed from cs.NI
Enabling Programmable Inference and ISAC at the 6GR Edge with dApps
Michele Polese, Rajeev Gangula and Tommaso Melodia
The convergence of communication, sensing, and Artificial Intelligence (AI) in the
Radio Access Network (RAN) offers compelling economic advantages through shared spectrum and infrastructure. How can inference and sensing be integrated in the RAN infrastructure at a system level? Current abstractions in O-RAN and 3GPP lack the interfaces and capabilities to support (i) a dynamic life cycle for inference and Integrated Sensing and Communication (
ISAC)
algorithms, whose requirements and sensing targets may change over time and across sites; (ii) pipelines for AI-driven
ISAC, which need complex data flows, training, and testing; (iii) dynamic device and stack configuration to balance trade-offs between connectivity, sensing, and inference services. This paper analyzes the role of a programmable, software-driven, open RAN in enabling the intelligent edge for 5G and 6G systems. We identify real-time user-plane data exposure, open interfaces for plug-and-play inference and
ISAC models, closed-loop control, and AI pipelines as elements that evolutions of the O-RAN architecture can uniquely provide. Specifically, we describe how dApps - a real-time, user-plane extension of O-RAN - and a hierarchy of controllers enable real-time AI inference and
ISAC. Experimental results on an open-source RAN testbed demonstrate the value of exposing I/Q samples and real-time RAN telemetry to dApps for sensing applications.
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Systems and Control
Sampling-Horizon Neural Operator Predictors for Nonlinear Control under Delayed Inputs
Luke Bhan, Peter Quawas, Miroslav Krstic et al. (+1 more)
Modern control systems frequently operate under input delays and sampled state measurements. A common delay-compensation strategy is predictor feedback; however, practical implementations require solving an implicit ODE online, resulting in intractable computational cost. Moreover, predictor formulations typically assume continuously available state measurements, whereas in practice measurements may be sampled, irregular, or temporarily missing due to hardware faults. In this work, we develop two neural-operator predictor-feedback designs for nonlinear systems with delayed inputs and sampled measurements. In the first design, we introduce a sampling-horizon prediction operator that maps the current measurement and input history to the predicted state trajectory over the next sampling interval. In the second design, the neural operator approximates only the delay-compensating predictor, which is then composed with the closed-loop flow between measurements. The first approach requires uniform sampling but yields residual bounds that scale directly with the operator approximation error. In contrast, the second accommodates non-uniform, but bounded sampling schedules at the cost of amplified approximation error, revealing a practical tradeoff between sampling flexibility and approximation sensitivity for the control engineer. For both schemes, we establish semi-global practical stability with explicit neural operator error-dependent bounds. Numerical experiments on a 6-link nonlinear robotic manipulator demonstrate accurate tracking and substantial computational speedup of 25$\times$ over a baseline approach.
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All authors Luke Bhan, Peter Quawas, Miroslav Krstic, Yuanyuan Shi
Systems and Control
Predictor-Based Output-Feedback Control of Linear Systems with Time-Varying Input and Measurement Delays via Neural-Approximated Prediction Horizons
Luke Bhan, Miroslav Krstic and Yuanyuan Shi
Due to simplicity and strong stability guarantees, predictor feedback methods have stood as a popular approach for time delay systems since the 1950s. For time-varying delays, however, implementation requires computing a prediction horizon defined by the inverse of the delay function, which is rarely available in closed form and must be approximated. In this work, we formulate the inverse delay mapping as an operator learning problem and study predictor feedback under approximation of the prediction horizon. We propose two approaches: (i) a numerical method based on time integration of an equivalent ODE, and (ii) a data-driven method using neural operators to learn the inverse mapping. We show that both approaches achieve arbitrary approximation accuracy over compact sets, with complementary trade-offs in computational cost and scalability. Building on these approximations, we then develop an output-feedback predictor design for systems with delays in both the input and the measurement. We prove that the resulting closed-loop system is globally exponentially stable when the prediction horizon is approximated with sufficiently small error. Lastly, numerical experiments validate the proposed methods and illustrate their trade-offs between accuracy and computational efficiency.
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Systems and Control
Design of an embedded hardware platform for cell-level diagnostics in commercial battery modules
Gabriele Marini, Alessandro Colombo, Andrea Lanubile et al. (+2 more)
While battery aging is commonly studied at the
cell-level, evaluating aging and performance within battery modules remains a critical challenge. Testing
cells within fully assembled modules requires hardware solutions to access
cell-level information without compromising module integrity. In this paper, we design and develop a hardware testing platform to monitor and control the internal
cells of battery modules contained in the Audi e-tron battery pack. The testing is performed across all 36 modules of the pack. The platform integrates voltage sensors, balancing circuitry, and a micro-controller to enable safe, simultaneous
cell screening without disassembling the modules. Using the proposed testing platform,
cell voltage imbalances within each module are constrained to a defined reference value, and
cell signals can be safely accessed, enabling accurate and non-invasive
cell-level state-of-health assessments. On a broader scale, our solution allows for the quantification of internal heterogeneity within modules, providing valuable insights for both first- and second-life applications and supporting efficient battery pack maintenance and repurposing.
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All authors Gabriele Marini, Alessandro Colombo, Andrea Lanubile, William A. Paxton, Simona Onori
Signal Processing
Semantic Sensing: Toward a Task-Oriented Paradigm
Xiaoqi Zhang, J. Andrew Zhang, Chang Liu et al. (+3 more)
Sensing and communication are fundamental enablers of next-generation networks. While communication technologies have advanced significantly, the potential of sensing beyond conventional parameter estimation remains far from fully explored. To address these limitations, we propose semantic sensing (SemS), a framework that extends task-oriented sensing through explicit modeling and recovery of task-relevant environmental information. Specifically, we mathematically formulate how transmit waveforms and receiver processing jointly support the recovery of task-relevant semantics, thereby establishing SemS as a semantics-oriented transceiver design. Within this architecture, we formulate an information-theoretic objective that guides the sensing pipeline to maximize task-relevant information extraction under resource constraints. To solve this optimization problem, we develop a deep learning (DL)-based framework that jointly designs transmit waveform parameters and receiver representations. The framework is implemented in an orthogonal frequency division multiplexing (OFDM) system, featuring a semantic encoder that employs differentiable pilot selection to select informative time–frequency resources. At the receiver, we design a shared semantic decoder that estimates three semantic attributes, namely object category, proximity, and radial motion, to support target classification and approach warning through predefined task mappings. We also consider continuous target range estimation as a special case in which the semantic state and task output coincide. Numerical results demonstrate that the proposed semantic pilot design achieves superior classification accuracy and approach-warning Macro-F1 compared to reconstruction-based baselines, particularly under constrained resource budgets.
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All authors Xiaoqi Zhang, J. Andrew Zhang, Chang Liu, Weijie Yuan, Geoffrey Ye Li, Moeness G. Amin
Audio and Speech Processing
Asymmetric Encoder-Decoder Based on Time-Frequency Correlation for Speech Separation
Ui-Hyeop Shin and Hyung-Min Park
Speech separation in realistic acoustic environments remains challenging because overlapping speakers, background noise, and reverberation must be resolved simultaneously. Although recent time-frequency (TF) domain models have shown strong performance, most still rely on late-split architectures, where speaker disentanglement is deferred to the final stage, creating an information bottleneck and weakening discriminability under adverse conditions. To address this issue, we propose SR-CorrNet, an asymmetric encoder-decoder framework that introduces the separation-reconstruction (SepRe) strategy into a TF dual-path backbone. The encoder performs coarse separation from mixture observations, while the weight-shared decoder progressively reconstructs speaker-discriminative features with cross-speaker interaction, enabling stage-wise refinement. To complement this architecture, we formulate
speech separation as a structured correlation-to-filter problem: spatio-spectro-temporal correlations computed from the observations are used as input features, and the corresponding deep filters are estimated to recover target signals. We further incorporate an attractor-based dynamic split module to adapt the number of output streams to the actual speaker configuration. Experimental results on WSJ0-{2,3,4,5}Mix, WHAMR!, and LibriCSS demonstrate consistent improvements across anechoic, noisy-reverberant, and real-recorded conditions in both single- and multi-channel settings, highlighting the effectiveness of TF-domain SepRe with correlation-based filter estimation for
speech separation.
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