Signal Processing
Amplitude-Phase-Frequency Block Modulation for OFDM-ISAC with SI-Free PAPR Reduction and Pilotless Sensing
Bensheng Yang, Min Fan, Haitao Zhao et al. (+1 more)
Orthogonal Frequency Division Multiplexing (OFDM)-based integrated sensing and communication systems demand a unified waveform that simultaneously supports reliable data transmission, low peak-to-average power ratio (PAPR), and accurate channel sensing. Existing approaches multiplex communication and sensing across separate time or frequency resources, or rely on dedicated pilots for channel estimation, limiting system flexibility and increasing overhead. This paper proposes an amplitude-phase-frequency block modulation (APFBM) scheme for OFDM that achieves waveform-level integration of communication and sensing without resource partitioning. Information symbols are represented on the Stokes sphere and mapped to energy-normalized Jones vectors through an unambiguous rule that establishes a deterministic phase reference per block. This mapping exposes a commonphase degree of freedom inherent in the signal structure. At the transmitter, a grouped phase optimization
algorithm exploits this structural freedom to reduce the PAPR without side information (SI). At the receiver, the same deterministic phase structure enables a Viterbi-based maximum-likelihood (ML) sequence detection
algorithm that jointly recovers the optimization phases and estimates the block-wise channel amplitude and phase. No dedicated sensing pilots are required, as the sensing observables are extracted directly from the communication waveform. Closed-form error-rate and sensing-accuracy expressions are derived. Numerical simulations and over-the-air measurements on a software-defined
radio link confirm effective PAPR reduction, accurate channel sensing, reliable phase recovery, and stable channel state information reconstruction. The proposed scheme trades a moderate reduction in spectral efficiency for a unified waveform design that simultaneously delivers SI-free PAPR reduction and pilotless sensing.
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All authors Bensheng Yang, Min Fan, Haitao Zhao, Haiming Wang
Audio and Speech Processing
Time-Unconditional Generative Speech Enhancement via Autonomous Rectified Flow
Wen Zhang, Wenbin Jiang, Yang Zhang et al. (+1 more)
Most generative
speech enhancement methods rely on explicit time-step
embeddings for temporal conditioning. In this paper, we propose the Autonomous Rectified Flow framework, which challenges the necessity of such conditioning. Using a linear interpolation path, we show that the target vector field is inherently time-invariant. We further introduce a time-unconditional network that eliminates explicit time-step information and infers the denoising direction solely from the spatial relationship between the current state and the noisy observation. Predicting this target vector field is equivalent to modeling the noise distribution. By avoiding overfitting to temporal trajectories, the proposed autonomous design significantly improves generation quality, robustness, and inference efficiency.
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All authors Wen Zhang, Wenbin Jiang, Yang Zhang, Xiaofei Zhou
Audio and Speech Processing · Cross-listed from cs.SD
PolSeT: Polish Semantics of Timbre Dataset
Jan Jasiński
This data report introduces PolSeT (Polish Semantic Timbre), a
dataset designed to facilitate research in psychoacoustics and Music Information
Retrieval (MIR) in Polish and cross-cultural contexts. The
dataset contains data from two sequential experiments. Experiment 1 (N=60) was a free-verbalization task aimed at creating a lexicon of Polish semantic descriptors. Using 11 stimuli, a total of 1901 descriptors (701 unique) were gathered. Experiment 2 (N=105) utilized this lexicon to conduct a semantic differential study, where participants rated 18 instrument sounds on 8 bipolar scales, with repeated trials for reliability analysis. The released
dataset includes raw listener responses, comprehensive demographics (experience, gender, age), audio stimuli, and extracted acoustic features with Python extraction code. This
dataset addresses a gap in open timbre research data, providing both the qualitative linguistic groundwork and the quantitative ratings necessary for psychoacoustic research and the training of
multilingual semantic
embedding models.
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Audio and Speech Processing
Interpreting Content and Speaker Characteristics in Factorised Self-Supervised Subspaces
Kyle Janse van Rensburg, Benjamin van Niekerk and Herman Kamper
Self-supervised
speech features encode both content and speaker information. Recent work introduced an SVD-based factorisation method that decomposes these features into a shared content
matrix capturing temporal variation and speaker-specific transformations capturing static speaker characteristics. However, how information is organised within these components remains unclear. In this paper, we investigate how the dimensions of WavLM-factorised content and speaker subspaces correlate with
speech characteristics such as pitch, intensity, and voicing. We find that leading dimensions in the content space primarily capture intensity, higher-order formants, and voicing, while pitch is encoded in a later dimension. In contrast, the highest-variance speaker dimension is strongly associated with pitch and gender, with later dimensions capturing high-frequency variation. Intervention experiments show that manipulating these dimensions enables targeted control of
speech characteristics for
speech synthesis. Furthermore, modifying the content and speaker representations jointly provides fine-grained control over characteristics such as pitch and intensity.
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Signal Processing
ConsisFormer: Compute-Efficient Transformer for Wireless Foundation Models Based on Channel Consistency
Yuwei Wang, Li Sun, Tingting Yang et al. (+4 more)
Wireless foundation models (WFMs) have recently emerged as a promising paradigm for AI-native 6G networks, enabling universal channel representations adaptable to diverse communication and sensing tasks. Existing WFMs are predominantly built upon the
Transformer architecture, which delivers superior performance but incurs computational complexity proportional to the square of the input sequence length, posing a significant barrier to their deployment under stringent inference latency constraints. To address this issue, in this paper, we propose ConsisFormer, a compute-efficient
Transformer design based on short-term consistency of wireless channels, as a WFM backbone. By utilizing the observation that adjacent time or frequency instances share similar clusters of scatterers and thus exhibit similar channel characteristics, we develop an adaptive
token aggregation (ATA) module to dynamically merge neighboring channel state information (CSI)
tokens, thereby reducing the length of the
token sequence involved in self-
attention calculations to lower the computational cost. Furthermore, we propose a feature sequence interpolation (FSI) method to recover the full CSI representation based on the sparse feature sequence outputted from the
Transformer blocks, thus keeping the performance unaffected while ensuring low complexity. Moreover, we propose an aggregated auto-encoder (AAE) pre-training paradigm for WFMs, enabling robust channel representation learning from sparsified CSI
tokens via compression and recovery. Simulation results show that the proposed design reduces the computational complexity of WFM by over $83\%$ with negligible performance loss on various tasks including channel prediction, LoS/NLOS classification, beam prediction, and localization.
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All authors Yuwei Wang, Li Sun, Tingting Yang, Liwen Jing, Yuxuan Shi, Maged Elkashlan, Mérouane Debbah
Audio and Speech Processing
Investigating Human-Model Discrepancies in Speech Quality Assessment via Acoustic and Prosodic Perturbations
Masato Takagi, Masaya Kawamura, Reo Shimizu et al. (+1 more)
Mean opinion score (MOS) prediction models are widely used as proxy metrics in text-to-
speech (TTS) research, yet their ability to capture quality differences beyond acoustic fidelity remains unclear. We investigate this via controlled perturbations on
speech: acoustic degradation, prosodic errors, and manipulation of speaker-specific characteristics such as pitch and speaking rate. We obtained MOS predictions for these
speech samples from both human listeners and the model, and analyzed the differences in their perceptual characteristics. Results show that most models track acoustic degradation well, while all are insensitive to prosodic errors despite large subjective score drops. For speaker characteristics, models exhibit a double dissociation: strong mean fundamental frequency (F0) biases absent in human ratings, yet insensitivity to speaking rate and F0 variability that humans notice. These findings highlight limitations of scalar MOS prediction beyond acoustic fidelity.
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All authors Masato Takagi, Masaya Kawamura, Reo Shimizu, Yuma Shirahata
Image and Video Processing
SIMBA: ABidirectional Retrieval Forward Simulation Framework for Modeling FY-4A GIIRS Hyperspectral Infrared Radiances Toward NWP Applications
Jingdong Shen, Fu Wang*, Qifeng Lu et al. (+4 more)
Hyperspectral infrared observations are an important data source for numerical weather prediction (NWP) because they provide rich information on the vertical structure of atmospheric temperature and humidity. However, most existing deep learning methods mainly focus on one-way
retrieval from radiances to atmospheric profiles, while the reverse radiance simulation process and the consistency between atmospheric state space and radiance observation space are insufficiently considered. In this study, we propose SIMBA, a unified bidirectional
retrieval-forward simulation framework for FY-4A GIIRS hyperspectral infrared radiance modeling toward NWP applications. The framework jointly performs atmospheric profile
retrieval and radiance reconstruction, introduces a cycle-consistency constraint to strengthen the coupling between the two processes, and employs a bidirectional Mamba state-space module to capture long-range dependencies along pressure levels. Using collocated FY-4A GIIRS observations and ERA5 reanalysis data, the proposed method is evaluated for temperature
retrieval, specific humidity
retrieval, long-wave radiance reconstruction, and medium-wave radiance reconstruction. Experimental results show that SIMBA outperforms several representative deep learning baselines across both
retrieval and reconstruction tasks, while ablation experiments confirm the contribution of the bidirectional design and cycle-consistency mechanism. These results demonstrate that the proposed framework is effective for joint atmospheric profile
retrieval and hyperspectral infrared radiance modeling, and suggest potential for future Jacobian-related analysis and NWP-oriented extensions.
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All authors Jingdong Shen, Fu Wang*, Qifeng Lu, Hao Huang, Chunqiang Wu, Chi Yang, Xiaofang Liu
Audio and Speech Processing
Analyzing Language and Geographical Variation in Speech Representations Across 60 Indic Languages
Pavan Kumar J, Agneedh Basu, Pranav Bhat et al. (+4 more)
Self-supervised
speech encoders are often fine-tuned with
language supervision, which can overlook geographical variation. To understand the learned representations under joint supervision of
language and district compared to
language-only supervision, we fine-tune Whisper-base and Wav2Vec2.0-base for classification tasks with joint
language-district (386 classes) and
language-only classification (60
languages). The
language-district supervision improves district discrimination conditioned on
language in the
embedding space while strong marginal
language classification. We analyze the structure of the learned
embeddings using Normalized Conditional Mutual Information (NCMI), showing that
language-district supervision produces global
language clusters with structured within
language subclusters aligned to district variation, enhancing geographical separability without degrading
language-level organization.
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All authors Pavan Kumar J, Agneedh Basu, Pranav Bhat, Sujith Pulikodan, Visruth Sanka, Nihar Desai, Prasanta Kumar Ghosh
Audio and Speech Processing · Cross-listed from cs.CL
Light-weight Pronunciation Assessment via Discrete Speech Token Surprisal
Syeda Faiza Ahmed Sara and Shammur Absar Chowdhury
Training automated pronunciation assessment often relies on labeled learner errors or non-native corpora that are costly to collect. We propose a lightweight framework trained only on native
speech resources, operating unsupervised or lightly calibrated with a small set of scored utterances. At inference, learner
speech is discretized with an SSL encoder and a K-means codebook. A
token language model trained on native sequences computes surprisal where higher surprisal indicates phonotactic deviation. We add a transcript-guided Text2DUnit–DTW module that predicts native
token sequences from reference text and aligns them to acoustic
tokens to derive error-sensitive features. Surprisal and
alignment features are fused via simple regression. On SpeechOcean762, PCC improves from 0.60 to 0.66 with transcript guidance, near supervised baselines. Cross-
dataset evaluation on L2-ARCTIC shows consistent gains.
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Systems and Control · Cross-listed from math.OC
Semiglobal Input-Delay Tolerance Algorithm for Distributed Nonconvex Optimization of Networked Nonlinear Systems
Jing-Zhe Xu, Zhi-Wei Liu, Ming-Feng Ge et al. (+2 more)
This paper studies a class of distributed optimization problems in networked nonlinear systems (NNSs) subject to input delays and consensus constraints. It introduces input-delay tolerant semiglobal convergence (IDTSC), meaning that for any prescribed compact initial set there exists an admissible delay bound under which the optimal solution is computed within consensus constraints and all node states converge to the solution. Building on a hierarchical design and input-to-state stability analysis, a new semiglobal input-delay tolerant (SIDT)
algorithm is developed that practically achieves IDTSC for distributed optimization under the coupling between input delays and nonlinear dynamics. Further, by relaxing strict convexity requirements through the Polyak-Łojasiewicz condition, the SIDT
algorithm broadens its applicability to nonconvex optimization. Finally, numerical experiments corroborate the theory on NNSs with input delays.
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All authors Jing-Zhe Xu, Zhi-Wei Liu, Ming-Feng Ge, Yan-Wu Wang, Dinxin He
Audio and Speech Processing
Low-Burden Data Augmentation for Dysarthric ASR via Zero-Shot Voice Cloning
Satwinder Singh, Qianli Wang, Zihan Zhong et al. (+4 more)
Automatic
speech recognition remains unreliable for dysarthric
speech due to data scarcity and high inter-speaker variability. While synthetic data can address these gaps, traditional methods often require extensive speaker-specific data, reintroducing the collection bottleneck. We investigate zero-shot voice cloning as a low-burden augmentation strategy, using
Higgs Audio V2 to clone speakers in the TORGO
dataset. We fine-tune (FT) Whisper-medium on cloned, real, and hybrid data and evaluate on held-out real
speech. Compared to the zero-shot (31.62%), Clone FT achieved a competitive 26.00% WER, nearly matching the 24.44% and 25.12% seen with Real and Hybrid FT, respectively. Notably, Clone and Hybrid FT outperform Real FT for moderate-severe speakers. Clone FT achieves the best results (11.45% relative) in cross-corpus evaluation on the SAP-1102. These results suggest that zero-shot cloning provides scalable training data that circumvents the costly data collection bottleneck.
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All authors Satwinder Singh, Qianli Wang, Zihan Zhong, Clarion Mendes, Hasegawa-Johnson, Waleed Abdulla, Seyed Reza Shahamiri
Audio and Speech Processing
Improving End-to-End Speech Recognition for Dysarthric Speech through In-Domain Data Augmentation
Paban Sapkota, Hemant Kumar Kathania, Sudarsana Reddy Kadiri et al. (+1 more)
Dysarthric
speech recognition is crucial for facilitating effective communication among individuals with dysarthria. However, accurately recognizing dysarthric
speech poses significant challenges due to varying severity levels and limited data availability. In this paper, we explore data augmentation techniques for dysarthric automatic
speech recognition (ASR) systems by fine-tuning the End-to-End pre-trained Wav2Vec2 model, with a specific focus on severity levels. To address the challenges of data scarcity and the need for extensive data in fine-tuning pre-trained ASR systems for dysarthric
speech, we investigate four prominent data augmentation methods: Speaking-Rate Modification (SRM), Pitch Modification (PM), Formant Modification (FM), and vocal tract Length Perturbation (VTLP), tailored to different aspects of dysarthria. The study uses individually fine-tuned Wav2Vec2 models for each severity class as baseline systems. Additionally, we conducted severity-specific fine-tuning of the ASR model using augmented data. Results demonstrate distinct efficacy patterns for each augmentation technique across severity levels. The best WERs were achieved with SRM ($s$=0.8) for low (9.02%) and medium (38.11%) severities, and with PM ($\tau$=0.8) for high severity (55.15%), reflecting relative improvements of 30.02%, 16.64%, and 15.47%, respectively. These results confirm the effectiveness of the augmentation methods in improving dysarthric ASR performance.
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All authors Paban Sapkota, Hemant Kumar Kathania, Sudarsana Reddy Kadiri, Shrikanth Narayanan
Audio and Speech Processing
Systematic Study of Dysarthric Speech Recognition: Spectral Features and Acoustic Models
Paban Sapkota, Hemant Kumar Kathania, Mikko Kurimo et al. (+2 more)
The challenge associated with recognizing dysarthric
speech primarily arises from pronounced acoustic variability attributed to impaired articulatory precision. Past research has demonstrated improved recognition through the use of hybrid DNN/HMM sequence discriminative training. This paper presents a comprehensive investigation of various combinations of acoustic features tailored to different Acoustic Models, offering suitable feature selections for each. The incorporation of Pitch features notably improved recognition performance, especially for sentence recognition tasks involving dysarthric
speech. Through a systematic examination of the TORGO database, we have demonstrated the potential to enhance the performance of the state-of-the-art Factorized Time Delay Neural Network (F-TDNN) model for recognizing dysarthric
speech. Our methods, implemented with the F-TDNN model, resulted in a 4.65% relative improvement in isolated word recognition and a 4.63% relative improvement in sentence recognition for dysarthric
speech, compared to previous research. This improvement effectively compensates for
speech variability, attributable to our deliberate selection of the number of overlapping frames between consecutive training example chunks.
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All authors Paban Sapkota, Hemant Kumar Kathania, Mikko Kurimo, Sudarsana Reddy Kadiri, Shrikanth Narayanan
Audio and Speech Processing
Cross-Dataset, Age, and Gender Generalization: A Comprehensive Analysis of Fine-Tuning Strategies for Low-Resource Children's ASR
Abhijit Sinha, Hemant Kumar Kathania, Sudarsana Reddy Kadiri et al. (+1 more)
The challenge associated with recognizing dysarthric
speech primarily arises from pronounced acoustic variability attributed to impaired articulatory precision. Past research has demonstrated improved recognition through the use of hybrid DNN/HMM sequence discriminative training. This paper presents a comprehensive investigation of various combinations of acoustic features tailored to different Acoustic Models, offering suitable feature selections for each. The incorporation of Pitch features notably improved recognition performance, especially for sentence recognition tasks involving dysarthric
speech. Through a systematic examination of the TORGO database, we have demonstrated the potential to enhance the performance of the state-of-the-art Factorized Time Delay Neural Network (F-TDNN) model for recognizing dysarthric
speech. Our methods, implemented with the F-TDNN model, resulted in a 4.65% relative improvement in isolated word recognition and a 4.63% relative improvement in sentence recognition for dysarthric
speech, compared to previous research. This improvement effectively compensates for
speech variability, attributable to our deliberate selection of the number of overlapping frames between consecutive training example chunks.
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All authors Abhijit Sinha, Hemant Kumar Kathania, Sudarsana Reddy Kadiri, Shrikanth Narayanan
Image and Video Processing
Contour-Constrained Deformable Registration with Parameter Characterization for Head and Neck Surgical Guidance
Qingyun Yang, Jon S. Heiselman, Ayberk Acar et al. (+5 more)
With 890,000 annual new cases globally, head and neck squamous
cell carcinoma has one of the highest recurrence rates among solid malignancies. Although frozen section analysis is the standard of care for intraoperative margin assessment, accurately relocating detected positive margins on the resection bed remains challenging due to imprecise
alignment between resected specimens and their resection bed, compounded by post-resection mucosal tissue shrinkage. We present a biomechanics-driven deformable registration framework that corrects post-resection tissue deformation to provide intraoperative guidance. Our approach registers 3D specimen meshes to intraoperative resection bed point clouds using a deformable registration approach based on regularized Kelvinlet basis functions. The registration matches surface point clouds, fiducial landmarks, and boundary contour constraints that directly penalize perpendicular distance-to-agreement between specimen and resection bed boundaries. Across nine specimens from skin, buccal mucosa, and tongue sites, the overall mean target registration error was $11.11 \pm 4.07$ mm using rigid registration, which decreased to $8.20 \pm 2.68$ mm (26.19% reduction) using deformable registration without contour constraint. The proposed contour-constrained deformable registration further reduced the error to $5.62 \pm 2.28$ mm, a 49.41% reduction relative to rigid registration. We observed the largest reduction in the most clinically challenging tongue specimens. We also performed a systematic two-stage parameter search to characterize the relative importance of surface
alignment, fiducial correspondences, contour constraint, and strain energy regularization. This search revealed that contour weighting dominates registration accuracy for tissue types with large lateral deformation, while the
algorithm operates over a broad range of parameter combinations.
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All authors Qingyun Yang, Jon S. Heiselman, Ayberk Acar, Morgan J. Ringel, Michael I. Miga, Matthieu Chabanas, Michael C. Topf, Jie Ying Wu
Signal Processing
Cyclic-Prefix OFDM Probing for Spatial-ISI-Free Distributed Acoustic Sensing via Frequency-Domain Channel Reconstruction
Huan Huang, Zhiyang Xue, Ziang Chen et al. (+4 more)
Nonzero sidelobes in matched-filter pulse-compression distributed acoustic sensing (DAS) cause deterministic inter-range-bin leakage, termed spatial inter-symbol interference (ISI), and may produce false Rayleigh-backscatter responses. We propose a data-bearing cyclic-prefix orthogonal frequency-division multiplexing (CP-OFDM) DAS system for phase-sensitive optical time-domain reflectometry (phi-OTDR), using the same waveform for probing and forward communication. To our knowledge, this is the first formulation of distributed Rayleigh backscattering as a finite-
memory sensing multipath channel. We rigorously prove that, when the useful OFDM and CP lengths cover the channel
memory, the receiver reconstructs range-bin coefficients without deterministic waveform-induced spatial ISI. CP removal, one-tap frequency-domain equalization, and inverse discrete
Fourier transform provide the reconstruction for subsequent gauge-differential phase demodulation. In a simulated 5.2-km link with ten simultaneous strong and weak events spaced 5.31-5.83 m within groups, CP-OFDM suppresses off-event spatial-ISI leakage. Phase-trace mean-square error improves by up to 29.55 dB over matched-filter pulse compression. A heterodyne coherent experiment over 5.2 km at a 111.984-MHz occupied bandwidth recovers 500-Hz vibrations near 80 m under 1- and 5-V piezoelectric transducer drives. Under identical probing conditions, CP-OFDM improves the vibration-to-background ratio by approximately 3.2 and 6.2 dB, respectively, over matched-filter linear frequency-modulated pulse compression while preserving local waveforms. The same probe recovers an image with zero measured bit-error rate and a median error vector magnitude of -23.14 dB. These results validate spatial-ISI-free DAS reconstruction and provide an initial demonstration of shared-waveform optical-fiber integrated sensing and communication (
ISAC).
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All authors Huan Huang, Zhiyang Xue, Ziang Chen, Zhongxing Tian, Dongdong Zou, Gangxiang Shen, Yi Cai
Signal Processing
An Optimization Framework for Certain Separable Problems using Neural Networks
Rohit Negi and Soummya Kar
This paper studies a class of parametric constrained optimization problems that are motivated by applications in real time applications. Under a parameter-separable problem structure that naturally arises in these applications, the paper proposes a two phase strategy, based on offline learning and online processing, to address these optimization problems on resource limited devices. Specifically, by exploiting the separable structure, an iterative Alternating Direction Method of Multipliers (ADMM) based solution procedure is developed that enables the use of certain learning based function representations (learned offline but readily computable online) to reduce the overall online on-device implementation complexity. By carefully crafting the ADMM procedure, it is shown that even as the parameters vary, the corresponding instances of the parametric optimization problem may be solved by lightweight online computations in the device with the assistance of a neural network co-processor.
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Signal Processing
Generalized Pinching-Antenna Systems: A Radio-Stripe-Based Realization
Yanqing Xu, Zhiguo Ding and Tsung-Hui Chang
This paper investigates
radio stripes (RSs) as a practical realization of generalized pinching
antennas and proposes an RS-based generalized pinching-
antenna (RS-GPA) framework. Unlike dielectric-waveguide-based passive pinching
antennas that rely on passive coupling from a guided wave into free space, RSs employ active
antenna processing units (APUs) deployed along a shared cable for local transmission, reception, and signal processing. This cable-like active architecture offers flexible installation and broad frequency applicability, while allowing selected APUs to act as discrete and controllable radiation or reception points for location-flexible wireless access. Based on the proposed RS-GPA framework, we establish the system and channel models by accounting for the distance-dependent APU-user channels. For downlink transmission, we formulate a
circuit-power-aware sparse APU activation and beamforming problem and develop a reweighted group-sparse beamforming
algorithm. To reveal the activation principle, we analyze the single-user downlink case and characterize when an additional APU should be activated by balancing transmit-power saving and
circuit-power cost. Inspired by this insight, a geometry-guided low-complexity multiuser
algorithm is proposed. For uplink transmission, we formulate a joint APU activation and user power control problem and develop a geometry-guided sparse activation design. Numerical results show that the proposed RS-GPA framework substantially reduces the total consumed power compared with
benchmark schemes, while the geometry-guided
algorithm achieves near-identical consumed-power performance to the group-sparse design with significantly lower runtime.
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Systems and Control · Cross-listed from cs.RO
A Differentiable Composite Approximation Framework for Autonomous Underwater Vehicle Maneuvering Modeling from Sea-Trial Data
Aobo Wang, Aifei Xia, Zihao Wang et al. (+1 more)
Field-based modeling from onboard measurements can produce autonomous
underwater vehicle (AUV) maneuvering models that reflect real operating characteristics. From an approximation perspective, conventional maneuvering models use predefined constraint
polynomial bases, whereas data-driven models use data-adaptive bases. Motivated by this basis-function view, this paper presents a differentiable composite-approximation formulation, in which the
polynomial-basis component and the data-adaptive basis component are treated as differentiable parts of a single predictor and calibrated jointly. A gradient-based co-calibration method is developed for full-scale AUV maneuvering prediction, where a sensitivity-aware mechanism regulates bounded
polynomial updates while the neural residual captures remaining nonlinear discrepancies under a shared prediction objective. To account for ocean-current effects in field data, a turning-motion-based current estimation and compensation procedure is incorporated to construct current-compensated learning targets for training and rollout. The framework is evaluated using sea-trial data collected from a 7-meter AUV under multiple maneuvering conditions. Results show that the proposed method improves recursive trajectory and velocity prediction compared with
polynomial-only, neural-only, and frozen-prior hybrid baselines, demonstrating its applicability to field-data-based AUV maneuvering modeling.
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All authors Aobo Wang, Aifei Xia, Zihao Wang, Lizhu Hao
Systems and Control · Cross-listed from cs.RO
Comparative Study on Agility, Efficiency, and Impact Absorption of Bipedal Robots with Active Toes
Joong-Gil Kim, Wontae Ye, Geunwoo Cho et al. (+3 more)
Human legs exhibit high efficiency, agility, and impact absorption, with toes playing a crucial role in these capabilities. While many attempts have been made to implement human-like toes in
robots, they have not fully replicated human characteristics nor rigorously validated their benefits. We propose a 14-DOF biped
robot emulating human toes' lightweight, high-torque, robust nature. To quantitatively analyze the effectiveness of the active toes in terms of agility, efficiency, and impact absorption, we developed a high-fidelity simulation training environment that reflects actual actuators with coupled transmissions and accurate power consumption. To ensure a fair comparison between configurations with and without active toes, we designed a minimal RL reward function and applied an identical training procedure to both. The simulation results indicate that, at 1.33 m/s walking, the toe-equipped
robot reduced CoT by 17.5% and heel-strike GRF by 5.0% compared with the toe-ablation configuration. On the agility test, average and maximum path deviation decreased by 25.0% and 34.0%, respectively.
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All authors Joong-Gil Kim, Wontae Ye, Geunwoo Cho, Seong-Ho Yun, Se-Hyoung Cho, Yong-Jae Kim
Systems and Control
A Unified Framework for Joint Sensor Placement and Scheduling for Intrusion Detection
Jayanth Bhargav, Mahsa Ghasemi and Shreyas Sundaram
We consider an intrusion detection task in which a defender must jointly optimize sensor placement locations and orientations to minimize the probability of missed detection of an intruder traversing a protected environment. We decompose this problem into a meta problem, termed SensorPlacement, and an embedded subproblem, termed OrientationScheduling. The OrientationScheduling subproblem, for a fixed sensor placement, is modeled as a 2-player zero-sum game between the defender and the intruder, where the defender seeks an orientation strategy for the deployed sensors to minimize the probability of missed detection, while the intruder seeks a path selection strategy to maximize it. Since the defender's strategy space grows combinatorially with the number of sensors and orientations, solving the game via standard linear programming becomes prohibitive. To this end, we develop an iterative and efficient
equilibrium-seeking
algorithm that exploits the structure of the game's payoff function and establishes theoretical guarantees for convergence to the Nash
equilibrium (NE) of the game. This NE value is then used as a utility measure in the SensorPlacement meta problem. We show that this game-value-based utility function is weakly submodular over the set of sensor placements and propose a greedy placement
algorithm with near-optimality guarantees. To our knowledge, this is the first unified framework to integrate game-theoretic utility design with (weak) submodular optimization, enabling principled joint optimization of sensor placement and orientation scheduling. Through extensive simulations, we demonstrate that the proposed approach achieves near-optimal detection performance while significantly reducing computation time compared to baselines.
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Audio and Speech Processing · Cross-listed from cs.SD
Latency-Configurable Streaming Speech Enhancement via Asymmetric Temporal Padding
Yunsik Kim and Yoonyoung Chung
Streaming
speech enhancement requires balancing algorithmic latency against quality, yet existing approaches largely treat this as a binary causal versus non-causal choice. LaCo-SENet addresses this issue with two mechanisms parameterized by a single training-time hyperparameter. First, asymmetric temporal padding redistributes past and future context in convolutions, enabling systematic latency configuration. Second, dual-buffer streaming combines state buffers for past context with lookahead buffers that supply future context at both the input and feature levels. Selective state updates also prevent future-frame leakage into the streaming state, ensuring training-inference consistency. On VoiceBank+DEMAND, a fixed-budget (1.37M parameters) backbone yields a family of models spanning 12.5-75.0 ms, with PESQ rising from 3.35 to 3.43. At just 12.5 ms (fully causal), a PESQ of 3.35 matches or exceeds the prior causal state-of-the-art (3.27 at 46.5 ms).
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Systems and Control · Cross-listed from cs.AI
Exit-and-Join Dynamics for Decentralized Coalition Formation
Quanyan Zhu
This paper studies coalition formation as a decentralized dynamical process driven by unilateral exit-and-join decisions.
Agents evaluate local moves using the Aumann-Dreze value, so payoffs are computed within the
agent's current coalition rather than through a globally negotiated coalition structure. The resulting model links cooperative payoff allocation with noncooperative best-response behavior: a terminal partition is precisely a coalition structure with no admissible, individually profitable exit-and-join deviation. We establish
equilibrium characterizations, identify conditions under which the dynamics admit scalar Lyapunov or exact-potential representations, and analyze how switching and acceptance costs shape local stability. Numerical experiments test finite-time stabilization, cost sensitivity, and a special convex-game
benchmark.
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Systems and Control · Cross-listed from math.OC
Learning Neural Maximal Lyapunov Functions on $\mathsf{SO}(n)$
Adeel Akhtar and Matthieu Barreau
Establishing stability guarantees for dynamical systems on Lie groups is a fundamental challenge, as classical Lyapunov methods developed for Euclidean spaces do not directly transfer to curved geometries. In this paper, we propose a framework for learning maximal Lyapunov functions for systems evolving on the special orthogonal group $\mathsf{SO}(n)$. Theoretically, we introduce a neural Lyapunov architecture based on the logarithmic map with proven approximation capabilities, and we formulate the learning problem via a Zubov-type characterization of the maximal region of attraction. A key technical contribution is the derivation of explicit, numerically tractable formulas for the derivative of the logarithmic map, enabling training through a two-phase
algorithm that balances computational efficiency and accuracy. Empirically, we validate the approach on a low-dimensional nonlinear system.
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Signal Processing
Degrees of Freedom and Beamforming for Large Intelligent Surfaces
Jiawang Li, Alireza Saberkari, Buon Kiong Lau et al. (+1 more)
Spatial degrees of freedom (DoF), sampling, and beamforming are fundamental to multi-user large intelligent surfaces (LISs), where electromagnetic fields must be shaped, resolved, and focused at multiple near-field locations. This work estimates the number of DoF using closed-form expressions derived from the mutual shadow area for representative LIS configurations. The resulting DoF predictions are validated through numerical singular-value spectra, whose spectral knee points closely match the theoretical estimates. For line-source configurations, an analytic sampling scheme is developed by partitioning the source or observation line into unit-DoF intervals, enabling the selection of spatial samples. Beamforming results using maximum-ratio transmission and zero-forcing demonstrate that approximately the number of DoF independent beams can be formed. Attempting to exceed this limit results in increased interference and degraded performance. For surface-based LIS configurations, sampling points are instead determined numerically using the discrete empirical interpolation method. The corresponding beamforming results further confirm that the target region can support approximately as many independent beams as predicted by the DoF analysis. Finally, a polarization-aware study reveals that the electric-field components contribute unequally to the DoF and that the total-field DoF is twice that of a single polarization component.
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All authors Jiawang Li, Alireza Saberkari, Buon Kiong Lau, Mats Gustafsson