Signal Processing · Cross-listed from physics.ins-det
CryoDE: a Digital Cryogenic Detector Emulator for Microwave SQUID Multiplexed Systems
Timo Muscheid, Daniel Crovo, Robert Gartmann et al. (+4 more)
Simultaneous readout of large-scale cryogenic detector arrays relies on multiplexing schemes such as the FDM (Frequency-Division Multiplexing) with microwave SQUID multiplexers and highly customized readout electronics. In traditional detector systems, where mixed-signal ASICs are used in detector front-ends and typically provide a digital interface, HIL (Hardware-in-the-Loop) testing can be readily implemented by reusing the existing digital logic of the front-end for emulation purposes. Such straightforward emulation is not possible for FDM low-temperature detectors, where the sensor signal is encoded in a high-frequency microwave carrier via a two-stage modulation scheme depending on the cryogenic resonators and the SQUID response. To address this challenge, we present CryoDE, a digital cryogenic-detector emulator for microwave SQUID multiplexed detector systems. CryoDE generates the encoded detector signals, including realistic pulse responses, enabling full HIL testing of the room-temperature DAQ system without requiring the cryogenic hardware. This resource-efficient FPGA-based detector twin integrates seamlessly into existing DAQ systems and allows experiment-specific adjustment of detector-signal parameters. We describe the internal architecture and capabilities of CryoDE within our custom HIL framework and demonstrate its use in evaluating the performance of real-time signal processing firmware optimized for different microwave SQUID multiplexed cryogenic-detector experiments.
Read the full abstract ▾
All authors Timo Muscheid, Daniel Crovo, Robert Gartmann, Eduardo Gerlein, Oliver Sander, Sebastian Kempf, Luis E. Ardila-Perez
Audio and Speech Processing · Cross-listed from q-bio.NC
Decoding Selective Auditory Attention to Musical Elements in Ecologically Valid Music Listening
Taketo Akama, Zhuohao Zhang, Tsukasa Nagashima et al. (+3 more)
Art has long played a profound role in shaping human
emotion, cognition, and behavior. While visual arts such as painting and architecture have been studied through eye tracking, revealing distinct gaze patterns between experts and novices, analogous methods for auditory art forms remain underdeveloped. Music, despite being a pervasive component of modern life and culture, still lacks objective tools to quantify listeners'
attention and perceptual focus during natural listening experiences. To our knowledge, this is the first attempt to decode selective
attention to musical elements using naturalistic, studio-produced songs and a lightweight consumer-grade
EEG device with only four electrodes. By analyzing neural responses during real world like music listening, we test whether decoding is feasible under conditions that minimize participant burden and preserve the authenticity of the musical experience. Our contributions are fourfold: (i) decoding music
attention in real studio-produced songs, (ii) demonstrating feasibility with a four-channel consumer
EEG, (iii) providing insights for music
attention decoding, and (iv) demonstrating improved model ability over prior work. Our findings suggest that musical
attention can be decoded not only for novel songs but also across new subjects, showing performance improvements compared to existing approaches under our tested conditions. These findings show that consumer-grade devices can reliably capture signals, and that neural decoding in music could be feasible in real-world settings. This paves the way for applications in education, personalized music technologies, and therapeutic interventions.
Read the full abstract ▾
All authors Taketo Akama, Zhuohao Zhang, Tsukasa Nagashima, Takagi Yutaka, Shun Minamikawa, Natalia Polouliakh
Systems and Control
Solving Multiparametric Generalized Nash Equilibrium Problems and Explicit Game-Theoretic Model Predictive Control
Sophie Hall and Alberto Bemporad
We present a method for computing explicit solutions to parametric generalized Nash
equilibrium (GNE) problems with convex quadratic cost functions and linear coupling and local constraints. Assuming that the parameters enter only the linear terms of the cost functions and the constraint right-hand sides, we provide the exact multiparametric solution of the GNE problem. Such a solution enables: (i) minimal real-time computation; (ii) inherent interpretability and explainability, as well as exact enumeration of all multiple
equilibria; (iii) selection of desired GNE solution types in the case of infinitely many
equilibria; and (iv) zero-shot updates of the GNE solution in response to changes in constraint right-hand sides and/or linear costs. In line with explicit model predictive control (MPC) approaches, we apply our method to solve game-theoretic MPC problems, also known as receding horizon games, explicitly. We compare its performance against centralized solvers in a battery charging game and a toy two-mass-spring-damper system control problem. A Python implementation of the
algorithms presented in this paper is available at https://github.com/bemporad/nash_mpqp.
Read the full abstract ▾
Signal Processing · Cross-listed from q-bio.NC
SSDLabeler: Realistic semi-synthetic data generation for multi-label artifact classification in EEG
Taketo Akama, Akima Connelly, Shun Minamikawa et al. (+1 more)
EEG recordings are inherently contaminated by artifacts such as ocular, muscular, and environmental noise, which obscure neural activity and complicate preprocessing. Artifact classification offers advantages in stability and transparency, providing a viable alternative to ICA-based methods that enable flexible use alongside human inspections and across various applications. However, artifact classification is limited by its training data as it requires extensive manual labeling, which cannot fully cover the diversity of real-world
EEG. Semi-synthetic data (SSD) methods have been proposed to address this limitation, but prior approaches typically injected single artifact types using ICA components or required separately recorded artifact signals, reducing both the realism of the generated data and the applicability of the method. To overcome these issues, we introduce SSDLabeler, a framework that generates realistic, annotated SSDs by decomposing real
EEG with ICA, epoch-level artifact verification using RMS and PSD criteria, and reinjecting multiple artifact types into clean data. When applied to train a multi-label artifact classifier, it improved accuracy on raw
EEG across diverse conditions compared to prior SSD and raw
EEG training, establishing a scalable foundation for artifact handling that captures the co-occurrence and complexity of real
EEG.
Read the full abstract ▾
All authors Taketo Akama, Akima Connelly, Shun Minamikawa, Natalia Polouliakh
Systems and Control · Cross-listed from cs.RO
Temporal Reach-Avoid-Stay Control for Differential Drive Systems via Spatiotemporal Tubes
Ratnangshu Das, Ahan Basu, Christos Verginis et al. (+1 more)
This paper presents a computationally lightweight and robust control framework for differential-drive mobile
robots with dynamic uncertainties and external disturbances, guaranteeing the satisfaction of Temporal Reach-Avoid-Stay (T-RAS) specifications. The approach employs circular spatiotemporal tubes (STTs), characterized by smoothly time-varying center and radius, to define dynamic safe corridors that guide the
robot from the start region to the goal while avoiding obstacles. In particular, we first develop a sampling-based synthesis
algorithm to construct a feasible STT that satisfies the prescribed timing and safety constraints with formal guarantees. To ensure that the
robot remains confined within this tube, we then analytically design a closed-form control that is computationally efficient and robust to disturbances. The proposed framework is validated through simulation studies on a differential-drive
robot and benchmarked against state-of-the-art methods, demonstrating superior robustness, accuracy, and computational efficiency.
Read the full abstract ▾
All authors Ratnangshu Das, Ahan Basu, Christos Verginis, Pushpak Jagtap
Systems and Control
Privacy-Preserving Fully Distributed Gaussian Process Regression
Yeongjun Jang, Kaoru Teranishi, Jihoon Suh et al. (+1 more)
Although distributed Gaussian process regression (GPR) enables multiple
agents to jointly learn a model of the target function, its collaborative nature poses a risk of private data leakage. To address this, we propose a
privacy-preserving fully distributed GPR protocol based on secure multi-party computation, which hides each
agent's individual contribution from semi-honest coalitions of bounded size, beyond what is implied by the aggregated value. Building upon a secure distributed average consensus
algorithm, it guarantees that each
agent's local model practically converges to the same global model obtained by the standard distributed GPR. Formal
privacy guarantees are established within the simulation based security paradigm. The protocol is further extended to
privacy-preserving optimization of kernel hyperparameters, which is critical yet often overlooked in the literature. Experimental results demonstrate the effectiveness and practical applicability of the proposed method.
Read the full abstract ▾
All authors Yeongjun Jang, Kaoru Teranishi, Jihoon Suh, Takashi Tanaka
Signal Processing
Individual Channel Estimation for Beyond Diagonal Reconfigurable Intelligent Surfaces
Kangchun Zhao and Yijie Mao
Beyond Diagonal Reconfigurable Intelligent Surfaces (BD-RIS) has emerged as a promising
evolution of RIS technology. By enabling interconnections between RIS elements, BD-RIS architectures offer greater flexibility in wave manipulation compared to traditional diagonal RIS designs. However, these interconnections introduce new research challenges for channel estimation, making existing approaches developed for conventional diagonal RISs ineffective and significantly increasing pilot overhead. To address these challenges, we propose a novel individual channel estimation framework that separately estimates the BS-RIS channel, which typically remains static over time, and the RIS-user channels, which vary rapidly due to user mobility. Specifically, we develop a full-duplex (FD) approach to estimate the BS-RIS channel by leveraging its inherent sparsity. Following this, the RIS-user channels are estimated using a least squares (LS) approach. Numerical results demonstrate that the proposed framework achieves significantly higher channel estimation accuracy, particularly when the number of RIS elements is large, while substantially reducing pilot overhead compared to conventional cascaded channel estimation methods.
Read the full abstract ▾
Systems and Control
Hybrid modeling approach for better identification of building thermal network model and improved prediction
Sang woo Ham and Donghun Kim
The gray-box modeling approach, which uses a semi-physical thermal network model, has been widely used in building prediction applications, such as model predictive control (MPC). However, unmeasured disturbances, such as occupants, lighting, and in/exfiltration loads, make it challenging to apply this approach to practical buildings. In this study, we propose a hybrid modeling approach that integrates the gray-box model with a model for unmeasured disturbance. After reviewing several system identification approaches, we systematically designed the unmeasured disturbance model with a model selection process based on statistical tests to make it robust. We generated data based on the building model calibrated by real operational data and then trained the hybrid model for two different weather conditions. The Hybrid model approach demonstrates the reduction of RMSE approximately 0.2-0.9C and 0.3-2C on 1-day ahead temperature prediction compared to the Conventional approach for mild (Berkeley, CA) and cold (Chicago, IL) climates, respectively. In addition, this approach was applied for experimental data obtained from the laboratory building to be used for the MPC application, showing superior prediction performances.
Read the full abstract ▾
Image and Video Processing
Image Semantic Communication with Quadtree Partition-based Coding
Yinhuan Huang and Zhijin Qin
Deep learning based semantic communication (DeepSC) system has emerged as a promising paradigm for efficient wireless transmission. However, existing image DeepSC methods, frequently encounter challenges in balancing rate-distortion performance and computational complexity, and often exhibit inferior performance compared to traditional schemes, especially on high-resolution
datasets. To address these limitations, we propose a novel image DeepSC system, using quadtree partition-based joint semantic-channel coding, named Quad-DeepSC, which maintains low complexity while achieving state-of-the-art transmission performance. Based on maturing learned image compression technologies, we establish a unified DeepSC system design and training pipeline. The proposed Quad-DeepSC integrates quadtree partition-based
entropy estimation and feature coding modules with lightweight feature extraction and reconstruction networks to form an end-to-end architecture. During training, all components except the feature coding modules are jointly optimized as a compact learned image codec, Quad-LIC, for source compression tasks. The pretrained Quad-LIC is then embedded into Quad-DeepSC and fine-tuned end-to-end over wireless channels. Extensive experimental results demonstrate that Quad-DeepSC is the first DeepSC system to surpass conventional communication systems, which employ VTM for source coding and adopt the optimal MCS index under 3GPP standards for channel coding and digital modulation, in performance across
datasets of varying resolutions. Notably, both Quad-DeepSC and Quad-LIC exhibit minimal latency, rendering them well-suited for deployment in real-time wireless communication systems.
Read the full abstract ▾
Systems and Control
Data-Driven Adaptive Output Regulation of Unknown Linear Systems
Shangkun Liu, Lei Wang and Bowen Yi
This paper investigates the linear output regulation problem with both the exosystem and the plant fully unknown. A data-driven regulator is proposed to achieve asymptotic regulation and closed-loop stability without performing model identification. The method constructs a nominal approximate internal model and filters of input and outputs, thereby yielding a stabilizable cascaded nominal system whose states are available. For this nominal system, a stabilizing law is derived from an offline
dataset that has been acquired from the plant during experiments, such that the system states exponentially converge to a subspace. An identifier in discrete-time is, then, implemented to correct the internal model and update the stabilizing law; as a result, the regulation error can be steered to zero asymptotically under some persistent excitation conditions.
Read the full abstract ▾
Signal Processing
Hardware-Impaired Over-the-Air Computation with Fluid Antenna Array
Zilong Li, Jianxin Dai, Zhaohui Yang et al. (+4 more)
This paper investigates a fluid
antenna (FA) array-enhanced over-the-air computation (AirComp) system in the presence of hardware impairments (HWIs), exploiting the new degrees of freedom offered by reconfigurable
antenna positioning. To minimize the mean squared error (MSE) of the aggregated signal, we jointly optimize transmit power control, receive beamforming, and the
antenna position vector (APV), subject to practical constraints such as HWI-induced distortion noise, FA movement energy consumption, and total power budgets. The resulting optimization problem is non-convex and highly coupled. To address it efficiently, we adopt a block coordinate descent (BCD) framework, decomposing it into three manageable subproblems. For each subproblem, closed-form solutions or efficient numerical
algorithms are derived. Simulation results demonstrate that the proposed joint transceiver and APV design significantly reduces the MSE compared to conventional fixed-position
antenna (FPA) arrays and exhibits enhanced robustness against hardware impairments. The effectiveness and convergence of the proposed
algorithm are further validated under various system configurations.
Read the full abstract ▾
All authors Zilong Li, Jianxin Dai, Zhaohui Yang, Zhaoyang Zhang, Kai-Kit Wong, Zhiyang Li, Shunkuan Cheng
Signal Processing
Noise Suppression for Time Difference of Arrival: Performance Evaluation of a Generalized Cross-Correlation Method Using Mean Signal and Inverse Filter
Hirotaka Obo, Yuki Fujita, Masahisa Ishii et al. (+4 more)
This paper proposes a novel generalized cross-correlation (GCC) method, termed GCC-MSIF, to improve time difference of arrival (TDOA) estimation accuracy in noisy environments. Conventional GCC methods often suffer from performance degradation under low signal-to-noise ratio (SNR) conditions, particularly when the signal bandwidth is unknown. GCC-MSIF introduces a "mean signal" estimated from multi-channel inputs and an "inverse filter" to virtually reconstruct the source signal, enabling adaptive suppression of out-of-band noise. Numerical simulations simulating a small-scale array demonstrate that GCC-MSIF significantly outperforms conventional methods, such as GCC-PHAT and GCC-SCOT, in low SNR regions and achieves robustness comparable to or exceeding the maximum likelihood (GCC-ML) method. Furthermore, the estimation accuracy improves scalably with the number of array elements. These results suggest that GCC-MSIF is a promising solution for robust passive localization in practical blind environments.
Read the full abstract ▾
All authors Hirotaka Obo, Yuki Fujita, Masahisa Ishii, Hideki Moriyama, Ryota Tsuchiya, Yuta Ohashi, Kotaro Seki
Systems and Control
Comparative Analysis of Barrier-like Function Methods for Reach-Avoid Verification in Stochastic Discrete-Time Systems
Zhipeng Cao, Peixin Wang, Luke Ong et al. (+3 more)
In this paper, we compare several representative barrier-like conditions from the literature for infinite-horizon reach-avoid verification of
stochastic discrete-time systems. Our comparison examines both their theoretical properties and computational tractability, highlighting each condition's strengths and limitations that affect applicability and conservativeness. Finally, we illustrate their practical performance through computational experiments using semidefinite programming (SDP) and counterexample-guided inductive synthesis (CEGIS).
Read the full abstract ▾
All authors Zhipeng Cao, Peixin Wang, Luke Ong, {\DJ}or{\dj}e Žikelić, Dominik Wagner, Bai Xue
Systems and Control · Cross-listed from stat.ML
Symmetric Linear Dynamical Systems are Learnable from Few Observations
Minh Vu, Andrey Y. Lokhov and Marc Vuffray
We consider the problem of learning the parameters of a $N$-dimensional
stochastic linear dynamics under both full and partial observations from a single trajectory of time $T$. We introduce and analyze a new
estimator that achieves a small maximum element-wise error on the recovery of symmetric dynamic
matrices using only $T=\mathcal{O}(\log N)$ observations, irrespective of whether the
matrix is sparse or dense. This
estimator is based on the method of moments and does not rely on problem-specific regularization. This is especially important for applications such as structure discovery.
Read the full abstract ▾
Signal Processing
Elevation- and Tilt-Aware Shadow Fading Correlation Modeling for UAV Communications
Mushfiqur Rahman, Ismail Guvenc, Mihail Sichitiu et al. (+4 more)
Future wireless networks demand a more accurate understanding of channel behavior to enable efficient communication with reduced interference. Uncrewed Aerial Vehicles (
UAVs) are poised to play an integral role in these networks, offering versatile applications and flexible deployment options. However, accurately characterizing the shadow fading (SF) behavior in
UAV communications remains a challenge. Traditional SF correlation models rely on spatial distance and neglect the
UAV's 3D orientation and elevation angle. Yet even slight variations in pitch angle (5 to 10 degrees) can significantly affect the signal strength observed by a
UAV. In this study, we investigate the impact of
UAV pitch and elevation geometry on SF and propose an elevation- and tilt-aware spatial correlation model. We use a real-world fixed-altitude
UAV measurement
dataset collected in a rural environment at 3.32 GHz with a 125 kHz bandwidth. Results show that a 10-degree tilt-angle separation and a 20-degree elevation-angle separation can reduce the SF correlation by up to 15% and 40%, respectively. In addition, integrating the proposed correlation model into the ordinary Kriging (OK) framework for signal strength prediction yields an approximate 1.5 dB improvement in median RMSE relative to the traditional correlation model that ignores
UAV orientation and elevation.
Read the full abstract ▾
All authors Mushfiqur Rahman, Ismail Guvenc, Mihail Sichitiu, Jason A. Abrahamson, Bryton J. Petersen, Amitabh Mishra, Arupjyoti Bhuyan
Image and Video Processing
CATNUS: Coordinate-Aware Thalamic Nuclei Segmentation Using T1-Weighted MRI
Anqi Feng, Zhangxing Bian, Samuel W. Remedios et al. (+6 more)
Accurate
segmentation of thalamic
nuclei from
magnetic resonance images is important due to the distinct roles of these
nuclei in overall
brain function and to their differential involvement in neurological and psychiatric disorders. However,
segmentation remains challenging given the small size of many
nuclei, limited intrathalamic contrast and image resolution, and inter-subject anatomical variability. In this work, we present CATNUS (Coordinate-Aware Thalamic
Nuclei Segmentation), segmenting 13 thalamic
nuclei (or
nuclear groups) using a 3D U-Net architecture enhanced with coordinate convolution layers, which provide more precise localization of both large and small
nuclei. To support broad clinical applicability, we provide pre-trained model variants that can operate on quantitative T1 maps as well as on widely used magnetization-prepared rapid gradient echo (MPRAGE) and fast gray matter acquisition T1 inversion recovery (FGATIR) sequences. We benchmarked CATNUS against established methods, including FreeSurfer, THOMAS and HIPS-THOMAS, demonstrating improved
segmentation accuracy and robust test-retest reliability across multiple
nuclei. Furthermore, CATNUS demonstrated strong out-of-distribution generalization on traveling-subject
datasets spanning multiple scanners, field strengths, and vendors, producing reliable and anatomically coherent
segmentations across diverse acquisition conditions. Overall, CATNUS provides an accurate and generalizable solution for thalamic
nuclei segmentation, with strong potential to facilitate large-scale neuroimaging studies and support real-world clinical assessment.
Read the full abstract ▾
All authors Anqi Feng, Zhangxing Bian, Samuel W. Remedios, Savannah P. Hays, Blake E. Dewey, Alexa Colinco, Jiachen Zhuo, Dan Benjamini, Jerry L. Prince