Signal Processing
Hybrid Digital and Microwave Linear Analog Computer (MiLAC)-aided Beamforming for Multiuser MIMO-OFDM Systems
Yiyang Peng, Zheyu Wu and Bruno Clerckx
Microwave linear analog computing (MiLAC) has recently emerged as a promising architecture for analog-domain beamforming. In particular, a hybrid digital-MiLAC architecture was proposed and was shown to achieve fully-digital beamforming flexibility in narrowband systems when the number of RF chains equals the number of data streams. However, its performance in wideband systems remains unexplored. This paper presents the first study of hybrid digital-MiLAC beamforming for wideband multi-user multiple-input single-output (MU-MISO) systems. We first characterize the minimum number of
radio-frequency (RF) chains required for hybrid digital-MiLAC beamforming to realize an arbitrary set of fully-digital beamforming
matrices across all subcarriers. It turns out that, unlike in the narrowband case, a larger number of RF chains is generally required in frequency-selective channels to achieve fully-digital beamforming flexibility, which may be unfavorable in practice. To study the performance of hybrid digital-MiLAC beamforming with a limited number of RF chains, we then formulate the average sum-rate maximization problem and develop an efficient weighted minimum mean-square error (WMMSE)-based
algorithm for beamforming design. Simulation results show that hybrid digital-MiLAC beamforming consistently outperforms conventional hybrid digital-analog beamforming, and achieves $89.93\%$ of the fully-digital sum-rate while using only $12.5\%$ of the RF chains in highly frequency-selective channels.
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Systems and Control · Cross-listed from cs.HC
Persona-Based Process Design for Assistive Human-Robot Workplaces for Persons with Disabilities
Nils Mandischer, Daria Eckert and and Lars Mikelsons
Human-
robot interaction is emerging as an important paradigm for integrating persons with disabilities into the workplace. While these systems can enable individuals to work, their design is mostly personalized, hindering widespread use beyond the individual user. The universal design paradigm is a central pillar of inclusive design, describing usability of systems by all. To incorporate universal design into process design for human-
robot workplaces expert knowledge is required that is often not available. To simplify process design of human-
robot workplaces, we propose a persona-based design approach. First, typical impairments prevalent in the workforce or particularly relevant for the processes are abstracted into personas with disabilities. The work process is subdivided into sequential actions. For each action and persona, strategies are developed to reach the action goal by a design thinking approach. The resulting actions are ordered by level of
robot assistance, i.e.
robot involvement, and implemented in a behavior tree. Therefore, the macro-behavior of the workplace may adapt to individual personas online. We demonstrate the method in a collaborative box folding process with a total of seven personas with disabilities. The persona-based process design shows promising results by generating more comprehensive process strategies while enabling adaptive behavior in the sense of universal design.
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Image and Video Processing
Adaptive Transform Coding for Semantic Compression
Andriy Enttsel and Vincent Corlay
Visual data compression is shifting from human-centered reconstruction to machine-oriented representation coding. In this setting, an image is often mapped to a compact semantic
embedding, which is then compressed and transmitted for downstream inference. We propose an adaptive transform-coding method for semantic-feature compression motivated by the conditional rate-distortion function of a Gaussian mixture model. The scheme uses mode-dependent transforms and quantizers selected according to the inferred source component, enabling more efficient coding of heterogeneous feature distributions. Evaluations on features from widely used
vision backbones and foundation models show that the proposed method outperforms or is competitive with state-of-the-art neural compression methods while preserving flexibility and interpretability.
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Systems and Control
Fuelling fusion plasmas with pellets: Can neuromorphic control outperform Sigma-Delta modulation?
L.L.T.C. Jansen, E. Petri, M. van Berkel et al. (+1 more)
Nuclear fusion is a promising clean energy source in which deuterium and tritium fuse inside a magnetically confined
plasma in a tokamak, releasing energy. A key challenge on the route to practical
nuclear fusion is the control of the
plasma density which has to be done through adding fuel in the form of deuterium and tritium to the
plasma. Pellet injection, firing frozen fuel into the
plasma, is used to accomplish this. Since the injection of a pellet causes an almost instantaneous increase in particle density compared to the time scales of the
plasma dynamics, the problem is of a hybrid nature in which continuous
plasma dynamics are interrupted by discrete bursts of particles. In this paper, we propose a formal hybrid model for this fuelling process and we propose a new,
neuron-inspired control method that treats pellets much like spikes as in a
brain-like system. The neuromorphic controller offers a lightweight solution that naturally fits the hybrid character of pellet fuelling. For comparison, we also develop a hybrid model of sigma-delta modulation, which is used in current tokamaks. For both the neuromorphic controller and the sigma-delta modulation we present formal analysis results for this control problem in
nuclear fusion. We derive explicit actuator and controller parameter constraints, key for controller tuning, that lead to practical stability guarantees. Numerical simulations compare the different controller variants and validate the theoretical results.
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All authors L.L.T.C. Jansen, E. Petri, M. van Berkel, W.P.M.H. Heemels
Signal Processing
CONCERTO : Optimization of readout electronics
Mounir Abdkrimi, Olivier Rossetto, Olivier Bourrion et al. (+2 more)
The CONCERTO millimeter-wave spectral-imaging instrument was deployed on the Atacama Pathfinder EXperiment (APEX), where it acquired science data between April 2021 and May 2023. The instrument features two focal-plane arrays, each composed of 2400 Microwave Kinetic Inductance Detectors (MKIDs). Each array is divided into six feedlines containing 400 MKIDs each, with each feedline read out by a dedicated FPGA-based board, KID_READOUT. The next-generation instrument aims to double the detector count per feedline, increasing it from 400 to 800 MKIDs. Achieving this requires a substantial scaling of the readout architecture and poses two key challenges for KID_READOUT: maintaining readout signal integrity and constraining firmware resource usage, as a direct upscaling of the existing design would exceed the available FPGA capacity. To overcome these limitations, we developed a Python-based, cycle-and bit-accurate digital twin of the full FPGA digital signal processing chain. This model enabled a detailed investigation of internal signal behavior and provided quantitative guidance for firmware optimization. Leveraging these insights, we identified the source of two spurs present in CONCERTO data and significantly reduced their amplitudes. At the same time, we achieved substantial reductions in firmware resource usage-39.0%pt in LUTs, 20.3%pt in flip-flops, and 28.98%pt in DSP slices-without degrading readout performance. The resulting architecture supports more than 800 MKIDs per feedline on the same hardware platform while preserving readout signal quality, offering a scalable and resource-efficient solution for future high-resolution millimeter-wave astronomical instruments.
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All authors Mounir Abdkrimi, Olivier Rossetto, Olivier Bourrion, Christophe Hoarau, Christophe Vescovi
Systems and Control
Risk-Aware Multi-Market Scheduling of Virtual Power Plants with Dynamic Network Tariffs
Lorenzo Zapparoli, Paul Fäth, Blazhe Gjorgiev et al. (+1 more)
As the penetration of distributed energy resources (DERs) increases, harnessing their flexibility becomes critical for power system operations. Virtual power plants (VPPs) offer a promising solution. However, most existing scheduling tools rely on simplified DER or grid models and largely overlook local flexibility procurement mechanisms such as dynamic network tariffs. This paper proposes a two-stage
stochastic optimization framework for VPP multi-
market scheduling that integrates detailed device-level constraints, network limitations, and operational and
market uncertainties. Conditional value-at-risk is incorporated to represent risk preferences, and Benders decomposition ensures tractability with extensive scenario sets. The model jointly optimizes bidding across energy and reserve
markets while explicitly accounting for local flexibility procurement through dynamic network tariffs. The results from a realistic case study show that both risk-neutral and risk-averse strategies exploit arbitrage opportunities. However, risk aversion reduces profit
volatility through closer
alignment with physical dispatch. Dynamic tariffs unlock local flexibility by shifting demand across the day, though strong tariff signals reduce expected profitability by up to 65% with limited additional flexibility gains.
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All authors Lorenzo Zapparoli, Paul Fäth, Blazhe Gjorgiev, Giovanni Sansavini
Signal Processing
A Novel Reinforcement Learning Based Framework for Scalable MIMO Interference Alignment
Samitha Gunarathne, Eslam Eldeeb, Nurul Huda Mahmood et al. (+1 more)
Interference
alignment (IA) is a widely recognized approach for mitigating inter-
cell interference in multi-user multiple-input multiple-output (
MIMO) networks. Despite its effectiveness, practical deployment remains constrained by two major challenges, i.e., the need for global channel state information (CSI) at each transmitter and the complexity of deriving closed-form solutions for intricate
MIMO systems. This work aims to maximize network throughput by effectively mitigating interference using an IA-inspired learning
algorithm that addresses its aforementioned challenges. First, we propose a predictive,
transformer-based IA framework that estimates CSI to reduce signaling overhead in small-scale
MIMO systems. Next, we formulate the IA problem as a multi-objective optimization problem based on subspace coordination and develop two reinforcement learning-based
algorithms to enhance the scalability of IA in large-scale
MIMO systems. Simulation results demonstrate that the proposed methods significantly outperform conventional baselines with up to 30% average user throughput gains over the best performing baseline.
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All authors Samitha Gunarathne, Eslam Eldeeb, Nurul Huda Mahmood, Italo Atzeni
Signal Processing
A Comparative study on THz Communication Systems: Photonics versus Electronics Approaches
Talha Rahman and Murat Uysal
Terahertz (THz) communication has emerged as a key enabler for sixth-generation (6G) networks, offering ultrawide bandwidths to support data-intensive applications such as
holographic telepresence and immersive extended reality. Recent advances have enabled both electronics-based and photonics-based THz front-ends, each with distinct advantages and hardware limitations. While electronics-based solutions leverage mature
semiconductor platforms, they suffer from amplified oscillator phase noise, frequency offsets, and nonlinearities introduced by multiplier and amplifier chains. Photonics-based systems, in turn, enable highly tunable and spectrally pure carriers but are subject to
laser intensity noise, amplified spontaneous emission, shot noise in photomixers, and thermal noise in RF mixers. This article provides a comprehensive review of experimental demonstrations in electronics-, photonics-, and hybrid-based THz links, highlighting their hardware architectures, performance metrics, and implementation trade-offs. We then survey theoretical modeling efforts, emphasizing how hardware impairments affect system reliability and identifying limitations in existing studies. Building on this, we develop comprehensive signal models for both approaches, derive analytical expressions for signal-to-noise ratio (SNR), and evaluate bit error rate (BER) performance under realistic system parameters. Comparative results demonstrate how distinct impairment mechanisms shape the overall link performance of electronics- versus photonics-based THz systems. The insights offered aim to guide the design of robust transceiver architectures and accelerate the integration of THz technologies into future 6G deployments.
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Signal Processing
A 21-24 GHz Low-Phase-Noise mmWave VCO with Third-Harmonic Expansion using a Triple-Coupled Transformer based Tank
Narahari N. Moudhgalya
This work presents the design and analysis of a sixth-order triple-coupled
transformer-based tank, enabling third-harmonic expansion for mmWave VCOs. Unlike conventional fourth-order tanks, the proposed tank inherently supports three resonance modes, enabling wideband third-harmonic expansion without additional low-Q switched-capacitor tuning elements. In contrast to conventional class-F23 designs, the proposed VCO removes the head resonator and adopts a noise circulating core to maintain low phase noise with reduced area. Implemented in TSMC 65-nm CMOS, post-layout simulation results demonstrate a 21.03-23.99 GHz (13.5%) tuning range, minimum phase noise of -116.25 dBc/Hz at 1 MHz offset, and peak FoM/FoMT/FoMA of 195.86/198.24/212.31 dBc/Hz while consuming 5.4 mW and occupying 0.02268 mm2.
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Systems and Control · Cross-listed from cs.SE
Asset Administration Shell-Based OCL Validation Framework for Model-Based System Engineering
Om Parkash, Jannik Bauer, Vincent Schmitt et al. (+2 more)
Increasing complexity of modern enterprise systems and the demand for automation and interoperability require consistent and semantically validated models in Model-Based Systems Engineering (MBSE). The Object Constraint
Language (OCL) supports formal definition of such constraint validations. However, MBSE models and OCL constraints are typically managed in separate tools, causing manual effort during model constraint application and result interpretation. To address this gap, this paper proposes an approach to managing OCL constraints and their validation results through Asset Administration Shells (a well-established technology for interoperability in enterprise systems). The methodology is demonstrated through a fictional industrial scenario, and to support reproducibility, all artifacts are publicly available in a GitHub repository.
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All authors Om Parkash, Jannik Bauer, Vincent Schmitt, Thomas Greiner, Rainer Drath
Audio and Speech Processing
The False Resonance: A Critical Examination of Emotion Embedding Similarity for Speech Generation Evaluation
Yun-Shao Tsai, Yi-Cheng Lin, Huang-Cheng Chou et al. (+5 more)
Objective metrics for emotional expressiveness are vital for
speech generation, particularly in expressive synthesis and voice conversion requiring emotional prosody transfer. To quantify this, the field widely relies on
emotion similarity between reference and generated samples. This approach computes cosine similarity of
embeddings from encoders like
emotion2vec, assuming they capture affective cues despite linguistic and speaker variations. We challenge this assumption through controlled
adversarial tasks and human
alignment tests. Despite high classification accuracy, these latent spaces are unsuitable for zero-shot similarity evaluation. Representational limitations cause linguistic and speaker interference to overshadow emotional features, degrading discriminative ability. Consequently, the metric misaligns with human perception. This acoustic vulnerability reveals it rewards acoustic mimicry over genuine emotional synthesis.
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All authors Yun-Shao Tsai, Yi-Cheng Lin, Huang-Cheng Chou, Tzu-Wen Hsu, Yun-Man Hsu, Chun Wei Chen, Shrikanth Narayanan, Hung-yi Lee
Signal Processing · Cross-listed from cs.CR
Can Cross-Layer Design Bridge Security and Efficiency? A Robust Authentication Framework for Healthcare Information Exchange Systems
Khalid M. Ezzat, Muhammad El-Saba and Mahmoud A. Shawky
As healthcare systems become increasingly interconnected, ensuring secure and continuous device authentication in health information exchange (HIE) networks is critical to safeguarding patient data and clinical operations. In this context, this paper proposes a novel cross-layer authentication scheme for HIE networks that integrates cryptographic mechanisms with physical (PHY) layer-based authentication to ensure reliable communication while minimizing computational and communication overheads. The initial authentication phase leverages a traditional public key infrastructure (PKI)-based approach, employing
elliptic curve cryptography (ECC) and digital certificates to verify the legitimacy of communicating devices. Simultaneously, it extracts unique hardware-level features such as carrier frequency offset (CFO) and quadrature skewness from the devices. These features are then used to train a machine learning (ML) model during an offline phase managed by a regional centralized authority (RCA). For re-authentication, the system re-extracts these PHY-layer features from incoming orthogonal frequency division multiplexing (OFDM) symbols and verifies the device identity in real-time using the trained ML classifier. This cross-layer strategy enables continuous, lightweight identity verification without the need to exchange and validate cryptographic signatures for each message, thereby reducing system overhead. The proposed scheme further enhances
privacy through the use of encrypted, frequently refreshed pseudo-identities, ensuring unlinkability and resistance to identity tracking. A formal security analysis using Burrows-Abadi-Needham (BAN) logic demonstrates the scheme's robustness against various threats, including impersonation, man-in-the-middle (MitM), replay, and Sybil attacks.
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Systems and Control
Real-Time Minimum-Energy Operating-Point Tracking for Battery-Powered Micro DC Motors Under Dynamically Variable Loading
Tzu-Hsiang Huang, Haojian Lu, Hen-Wei Huang et al. (+1 more)
Micro DC brushed motors are widely deployed in battery-powered biomedical systems, where limited energy budgets and variable physiological loading impose stringent efficiency and safety constraints. However, conventional actuation strategies rely on conservative voltage margins to avoid stalling, leading to systematic energy inefficiency. Furthermore, existing methods primarily optimize steady-state performance, neglecting the energy required to complete individual actuation cycles under dynamic conditions. This paper reveals that the energy consumption per mechanical cycle of a DC motor exhibits a non-monotonic dependence on driving voltage, with a load-dependent minimum that shifts with external loading. Based on this insight, we propose a real-time operating-point tracking method that enables the motor to autonomously converge to its minimum-energy condition. A lightweight load metric derived from current waveform features is introduced to detect load variation, and a two-phase adaptive voltage strategy is developed to track the optimal operating point online. Experimental results demonstrate that the proposed method can track the new minimum-energy operating region under both low-to-high and high-to-low loading transitions. With 3-cycle averaging, the mean response time is 11.55s for the low-to-high case and 11.16s for the high-to-low case, while the mean convergence voltage is 2.73V and 2.0V, respectively.
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All authors Tzu-Hsiang Huang, Haojian Lu, Hen-Wei Huang, Tan Rong
Signal Processing
Optimizing Tracking Accuracy in Energy-Constrained Multimodal ISAC via Lyapunov-Driven Heterogeneous Mixture-of-Experts
Wenqi Fan, Ning Wei, Ahmad Bazzi et al. (+6 more)
The integration of
multimodal sensing and millimeter-wave (mmWave) communications is a key enabler for highly mobile vehicle-to-infrastructure (V2I) networks. However, continuous high-resolution visual sensing incurs prohibitive computational energy, while delayed sensing information causes severe beam misalignment. This paper establishes a physics-aware
multimodal integrated sensing and communication (M-
ISAC) framework that mathematically bridges network-layer queuing delays with physical-layer spatial uncertainty via the semantic age of information (AoI). Guided by this relationship, we aim to strike an optimal trade-off between the tracking posterior Cramer-Rao bound (PCRB) and system energy budgets, we formulate a
stochastic mixed-integer non-linear programming (MINLP) problem. Addressing the coupled challenges of temporal computing congestion and non-convex constant modulus constraints, we propose a reinforcement learning (RL) framework empowered by a Lyapunov-driven heterogeneous mixture-of-experts (LD-H-MoE) architecture. By strictly decoupling temporal scheduling and spatial phase mapping into specialized subnetworks, the LD-H-MoE circumvents gradient conflicts prevalent in monolithic multi-task learning. Simulations demonstrate that the proposed LD-H-MoE achieves a highly-effective event-triggered sensing policy, yielding superior tracking accuracy and
radio-frequency (RF) resilience while guaranteeing edge computing queue stability and long-term energy budgets.
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All authors Wenqi Fan, Ning Wei, Ahmad Bazzi, Rongyan Xi, Zhixian Song, You Li, Zhihan Zeng, Yue Xiu, Chadi Assi
Audio and Speech Processing
Dual-LoRA: Parameter-Efficient Adversarial Disentanglement for Cross-Lingual Speaker Verification
Qituan Shangguan, Junhao Du, Kunyang Peng et al. (+5 more)
Cross-lingual speaker verification suffers from severe
language-speaker
entanglement. This causes systematic degradation in the hardest scenario: correctly accepting utterances from the same speaker across different
languages while rejecting those from different speakers sharing the same
language. Standard
adversarial disentanglement degrades speaker discriminability; blind discriminators inadvertently penalize speaker-discriminative traits that merely correlate with
language. To address this, we propose Dual-LoRA, injecting trainable task-factorized LoRA adapters into a frozen pre-trained backbone. Our core innovation is a
Language-Anchored Adversary: by grounding the discriminator with an explicit
language branch,
adversarial gradients target true linguistic cues rather than arbitrary correlations, preserving essential speaker characteristics. Evaluated on the TidyVoice
benchmark, our system achieves a 0.91% validation EER and achieves 3rd place in the official challenge.
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All authors Qituan Shangguan, Junhao Du, Kunyang Peng, Feng Xue, Hui Zhang, Xinsheng Wang, Kai Yu, Shuai Wang
Audio and Speech Processing
SPG-Codec: Exploring the Role and Boundaries of Semantic Priors in Ultra-Low-Bitrate Neural Speech Coding
Mingyu Zhao, Zijian Lin, Kun Wei et al. (+1 more)
Conventional neural
speech codecs suffer from severe intelligibility degradation at ultra-low bitrates, where the bottleneck transitions from acoustic distortion to semantic loss. To address this issue, this paper conducts a systematic investigation into the role and fundamental limits of integrating frozen semantic priors – specifically HuBERT and Whisper – into neural
speech coding. We introduce and quantitatively validate a novel Semantic Retirement phenomenon: while semantic constraints reduce the Word Error Rate (WER) by up to ~10% relatively at 1.5 kbps, their benefits rapidly diminish beyond 6 kbps, indicating a practical capacity boundary. We further uncover a clear trade-off between different prior types: acoustic-rich priors (HuBERT) better preserve prosodic and timbral details, whereas high-level linguistic priors (Whisper) effectively suppress phonetic
hallucinations in noisy environments (reducing
hallucination rates by 26 percent) and substantially narrow the generalization gap for unseen speakers. Building on these findings, we propose a bitrate-aware regulation strategy that dynamically adjusts prior strength to optimize the trade-off between semantic consistency and perceptual naturalness. Extensive experimental evaluations confirm that our approach achieves competitive intelligibility and noise robustness compared to existing baselines, offering a principled pathway toward ultra-low-bitrate generative
speech coding.
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All authors Mingyu Zhao, Zijian Lin, Kun Wei, Zhiyong Wu
Signal Processing · Cross-listed from cs.IT
Rethinking Mutual Coupling in Movable Antenna MIMO Systems: Modeling and Optimization
Tianyi Liao, Wei Guo, Jun Qian et al. (+4 more)
Movable
antennas (MAs) have attracted growing interest for their ability to improve channel conditions via adaptive
antenna movement. Nevertheless, such movement inevitably introduces mutual coupling (MC), whose impact has been largely overlooked in existing MA literature. In this paper, we show that MC is not merely an unavoidable electromagnetic effect, but also a new source of capacity gains in MA-enabled multiple-input multiple-output (
MIMO) systems. To leverage MC effects, we develop an optimization framework for both narrowband and wideband systems based on a rigorous
circuit-theoretic model. For narrowband systems, capacity maximization is formulated as a non-convex optimization problem, which is solved via a block coordinate ascent (BCA) framework. Because optimizing MA positions is challenging due to analytically intractable MC
matrices, we develop a trust region method (TRM)-based
algorithm that utilizes Sylvester equations to compute the derivatives of the inverse square roots of the MC
matrices. We further consider wideband systems and formulate a sum-rate maximization problem. To find a unified set of MA positions that balances varying subcarrier conditions, the BCA framework and the TRM-based MA position optimization
algorithm are extended to wideband systems. Simulation results demonstrate that exploiting MC effects in MA-
MIMO systems yields significant performance gains in both narrowband and wideband systems under various channel conditions. These gains highlight the benefits of MC-induced superdirectivity and designable MC
matrices.
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All authors Tianyi Liao, Wei Guo, Jun Qian, Zixin Wang, Shenghui Song, Jun Zhang, Khaled B. Letaief
Audio and Speech Processing
DiffAnon: Diffusion-based Prosody Control for Voice Anonymization
Ismail Rasim Ulgen, Zexin Cai, Nicholas Andrews et al. (+2 more)
To preserve or not to preserve prosody is a central question in voice anonymization. Prosody conveys meaning and affect, yet is tightly coupled with speaker identity. Existing methods either discard prosody for
privacy or lack a principled mechanism to control the utility-
privacy trade-off, operating at fixed design points. We propose DiffAnon, a
diffusion-based anonymization method with classifier-free guidance (CFG) that provides explicit, continuous inference-time control over prosody preservation. DiffAnon refines acoustic detail over semantic
embeddings of an RVQ codec, enabling smooth interpolation between anonymization strength and prosodic fidelity within a single model. To the best of our knowledge, it is the first voice anonymization framework to provide structured, interpolatable inference-time prosody control. Experiments demonstrate structured trade-off behavior, achieving strong utility while maintaining competitive
privacy across controllable operating points.
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All authors Ismail Rasim Ulgen, Zexin Cai, Nicholas Andrews, Philipp Koehn, Berrak Sisman
Audio and Speech Processing · Cross-listed from cs.SD
Recurrence-Based Nonlinear Vocal Dynamics as Digital Biomarkers for Depression Detection from Conversational Speech
Himadri S Samanta
Digital biomarkers for depression have largely relied on static acoustic descriptors, pooled summary statistics, or conventional machine learning representations. Such approaches may miss nonlinear temporal organization embedded in conversational vocal dynamics. We hypothesized that depression is associated with altered recurrence structure in vocal state trajectories, reflecting changes in how the vocal system revisits acoustic states over time. Using the depression subset of the DAIC-WOZ corpus with 142 labeled participants, we modeled frame-level COVAREP trajectories as nonlinear dynamical systems and derived recurrence-based biomarkers from 74 vocal channels. Logistic regression with feature selection and stratified cross-validation evaluated classification performance. Recurrence-based biomarkers achieved a mean cross-validated AUC of 0.689, exceeding static acoustic baselines,
entropy-dynamics features, Hurst exponent features, determinism features, and Lyapunov-like instability proxies. Permutation testing indicated statistical significance with $p=0.004$. Pooled cross-validated predictions yielded AUC 0.665 with a 95% bootstrap confidence interval of [0.568, 0.758]. These findings suggest that depression may be characterized by altered recurrence structure in conversational vocal dynamics and support nonlinear state-space analysis as a promising direction for digital psychiatric biomarkers.
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Image and Video Processing · Cross-listed from cs.NI
StreamGuard: Exploring a 5G Architecture for Efficient, Quality of Experience-Aware Video Conferencing
Xuyang Cao, Oliver Michel and Kyle Jamieson
Video conferencing over 5G is increasingly prevalent, yet its Quality of Experience (QoE) often degrades under limited
radio resources. This has two causes: 5G networks must serve many users, while interactive traffic requires careful handling. Motivated by the insight that different subflows within an interactive session have a disproportionate effect on QoE, we present the design and implementation of StreamGuard, a practical 5G architecture for subflow-level, QoE-aware prioritization. StreamGuard forms a closed control loop with three components: (1) a monitor in the
Radio Access Network (RAN) that uses deep packet inspection to infer QoE and RAN state, (2) a controller that selects prioritization actions to balance QoE and
fairness, and (3) a marking module that applies these decisions by marking packets to steer subflows into appropriate priority queues. StreamGuard further shapes application behaviors via mechanisms including selective subflow dropping and probe-based rate control, to align application behavior with
radio constraints. Implemented in a real 5G testbed, StreamGuard achieves a superior QoE-
fairness tradeoff compared to vanilla 5G and prior state-of-the-art approaches, improving QoE by up to 70% at comparable background throughput or preserving up to 2x higher background throughput at similar QoE.
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Signal Processing
Blind OFDM-ISAC Relying on Asymmetric Modem Constellations
Henglin Pu, Ahmad Musallam, Husheng Li et al. (+1 more)
Integrated sensing and communication (
ISAC) is increasingly expected to operate under aggressive spectrum reuse, where co-channel orthogonal frequency division multiplexing (OFDM) interference can be catastrophic for data recovery on the time-frequency (TF) grid. We show that supporting blind
ISAC is feasible by exploiting a fundamental asymmetry in the impact of co-channel OFDM interference: while communication is fragile on the TF grid, sensing depends on structured physical parameters whose signatures remain identifiable by relying on higher-order statistics. Based on this observation, we construct a fourth-order measurement tensor from the received OFDM signal whose coherent component preserves the delay-, Doppler-, and angle-dependent phase
evolution of each source. We then develop a three-dimensional higher-order-statistics (HOS) based periodogram for iterative peak search and refinement to jointly estimate both range, velocity, and angle in the presence of unknown co-channel interferers. We further exploit constellation asymmetry to resolve the remaining phase ambiguities of blind recovery, enabling blind coherent demodulation via minimum constellation fitting. We also
benchmark the performance through matched data-aided and
stochastic Cramer-Rao lower bounds. We then quantify the cost of signal blindness. Simulations and experimental validations demonstrate reliable radar parameter estimation together with effective communication demodulation even when the TF-domain link is severely interfered with.
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All authors Henglin Pu, Ahmad Musallam, Husheng Li, Lajos Hanzo