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2025-10-28
PIER M
Vol. 135, 100-111, 2025
download: 143
Identifying Autistic Children Using Deep Learning Based on the Temporal and Spatial Information of Eye-Tracking
Deyu Guo, Yan Zhang, Tengfei Ma, Xinhua Zhu and Sailing He
This study addresses the challenge of detecting Autism Spectrum Disorder (ASD) in children, where clinical diagnostic scales used in practice suffer from subjectivity and high costs. Eye tracking (ET), as a non-contact sensing technology, offers the potential for objective ASD recognition. However, existing studies often use specially crafted visual stimuli, making them less reproducible, or rely on the construction of handcrafted features. Deep learning methods allow us to build more efficient models, but only a few studies simultaneously focused on visual behaviors of ASD in both temporal and spatial dimensions, and many studies compressed the temporal dimension, potentially losing valuable information. To address these limitations, this study employed a relatively lenient visual stimulus selection criterion to collect ET data of ASD in social scenes, enabling analyses to be conducted both temporally and spatially. Findings indicate that the spatial attention distribution of ASD is more dispersed, and gaze trajectories are more unstable in the temporal dimension. We also observed that children with ASD exhibit slower responses in gaze-following scenarios. Additionally, data loss emerges as an effective feature for ASD identification. We proposed an SP-Inception-Transformer network based on CNN and Transformer encoder architecture, which can simultaneously learn temporal and spatial features. It utilized raw eye-tracking data to prevent information loss, and employed Inception and Embedding to enhance the performance. Compared to benchmark methods, our model demonstrated superior results in accuracy (0.886), AUC (0.8972), recall (0.82), precision (0.95), and F1 score (0.8719).
Identifying Autistic Children Using Deep Learning Based on the Temporal and Spatial Information of Eye-Tracking
2025-10-26
PIER M
Vol. 135, 91-99, 2025
download: 78
Broadband Full Functional Reconfigurable Polarization Converter Based on Active Metasurface
Ke Wang, Chao Zhang, Wei Li, Jun Fan, Chuan Shao, Yichao Zhou and Shijie Xie
This article proposes a novel polarization-reconfigurable metasurface converter with multi-functional operation capabilities for flexible polarization manipulation of electromagnetic waves. By integrating PIN diodes into a strategically designed unit cell, the converter achieves dynamic switching among all fundamental polarization conversion modes, including linear-to-linear (co- and cross-polarization), circular-to-circular (co- and cross-polarization), linear to circular polarization (LP-CP), and circular to linear polarization (CP-LP) conversions under both linearly and circularly polarized incidence. When the diodes are switched ON, the structure performs linear-to-cross-linear polarization conversion in the 9.5-16.4 GHz band and circular-to-co-circular polarization conversion in the 9.3-16.6 GHz band. Dual-band LP-CP and CP-LP conversions are attained in the 8.0-9.3/16.6-17.7 GHz and 8.1-9.4/16.8-17.9 GHz bands, respectively. When the diodes are OFF, the converter maintains co-polarized reflection under linearly polarized (LP) wave incidence, while reversing the handedness of the incident circularly polarized (CP) wave. Both full-wave simulations and experimental measurements demonstrate consistent performance across a broad bandwidth. This work provides a versatile and efficient solution for modern wireless communication and radar systems requiring adaptive polarization control.
Broadband Full Functional Reconfigurable Polarization Converter Based on Active Metasurface
2025-10-06
PIER M
Vol. 135, 80-90, 2025
download: 163
Dynamic Resources Management for Integrated Optimized Entanglement in Quantum Repeater Networks
Omar Ali Mohammad and Jawad A. K. Hasan
Quantum repeaters are essential for long-distance quantum communication, surmounting challenges like signal attenuation and decoherence. Nonetheless, current quantum repeater networks are constrained by static cutoff times for low-fidelity connections, suboptimal resource allocation, and the absence of quantum-classical integration. This paper introduces a hybrid quantum-classical method to tackle these issues by employing dynamic cutoff times contingent upon real-time fidelity decay and decoherence rates. Markov Decision Process (MDP) is used to characterize the system with the aim to optimize the entanglement generation processes, waiting and swapping. In this study, the objective is to reduce the time which is needed to realize end-to-end entanglement while fulfilling the requirements of classical channel capacity. To manage constraints such as classical user demands, quantum memory limits, and network congestion, Lagrangian optimization has been applied. The combined approach improves the use of both classical resources and quantum, providing a simplified solution that is adaptable to different users needs and different network conditions. The effectiveness of the model is tested via simulations processes, along with the mathematical process. This demonstrated important gains in fidelity preservation, resource efficiency, and latency minimization compared to the state-of-the-art traditional methods. This study makes a valuable contribution tackling the development of quantum networks, providing a rigid establishment to build a quantum capable for internet to support the security in distributed quantum computing and global communications.
Dynamic Resources Management for Integrated Optimized Entanglement in Quantum Repeater Networks
2025-10-04
PIER M
Vol. 135, 69-79, 2025
download: 109
Low Profile Meta-Surfaces Based Stacked Slotted Microstrip Antenna in a Ring for 5G Applications
Vijaypal Yadav, Meenakshi Awasthi and Rajiv Kumar Gupta
This paper proposes a stacked slotted microstrip antenna (MSA) using multiple meta-surfaces that offers high gain and stable radiation patterns for 5G applications. A metal plated suspended MSA (SMSA) in air is designed to enhance gain and band width (BW). However, impedance becomes inductive and cross-polarization level (CPL) increases with increase in probe feed length. To decrease the inductive impedance and increase the capacitance, a slot in SMSA is etched. A parasitic patch with meta-surfaces on a superstrate is placed above the slotted SMSA and a rectangular ring around the slotted MSA is designed to increase the inductance. To compensate it, substrate height is decreased. The decrease in probe feed length/substrate height, decreases the CPL. Parasitic patch, rectangular ring around slotted SMSA and meta-surfaces, electro-magnetically couple with SMSA and enhance the BW of antenna. The low-profile (0.979λ0 × 1.03λ0 × 0.064λ0, λ0 - wavelength in free-space at 3.3 GHz) antenna offers peak gain of 9.8 dBi, antenna efficiency > 80%; SLL and CPL are < -22 dB; and the gain variation is < 0.5 dB over the 3.3-3.6 GHz frequency band for 5G application. The substrate height of the proposed novel structure is 2.5 times less than SMSA, and it offers an improvement of 8.1 dB in CPL as compared to SMSA.
Low Profile Meta-surfaces Based Stacked Slotted Microstrip Antenna in a Ring for 5G Applications
2025-09-30
PIER M
Vol. 135, 55-68, 2025
download: 121
Synthesis of Miniaturized Frequency-Selective Surfaces Using Stepped Impedance Resonators for Spurious Shift Control
Salem Bousnadji, Larbi Talbi, Khelifa Hettak and Mohamed Mamdouh M. Ali
Frequency-Selective Surfaces (FSSs) are structures designed to selectively transmit or reflect electromagnetic waves, making them essential for applications requiring precise control over frequency bands and wave propagation characteristics. However, traditional FSS designs face challenges such as fixed geometries, limited scalability, and poor bandwidth efficiency, often requiring compromises between size reduction and performance. To address these limitations, this work introduces the use of Stepped Impedance Resonators (SIRs) to synthesize miniaturized FSS structures with four-legged elements (FLEs). By combining transmission line theory, SIR equations, and parallel coplanar stripline models, an innovative synthesis method is proposed, enabling precise control over spurious frequencies and resulting in a 54% reduction in unit-cell size without sacrificing performance. This approach significantly enhances the feasibility of compact FSS applications. To further improve performance, an arrow-bending technique was introduced to reduce the coupling between adjacent cells, yielding a 30% improvement in isolation. Three distinct surface designs have been fabricated and tested under both normal incidence and oblique angles for TE and TM modes. These designs include the SIR-based FSS cell, an enhanced design featuring arrow bending, and a reverse arrow formation intended to reduce edge effects between adjacent cells. Additionally, measurements demonstrate excellent performance stability, with tolerance maintained for incident angles up to 60°. Experimental validation confirms effective blocking at 10 GHz and highlights the robustness of the design across varying incident angles. Prototypes fabricated from the miniaturized FSS elements show excellent agreement with simulations, underscoring the potential of this method for advanced applications in communications, radar, and electromagnetic shielding.
Synthesis of Miniaturized Frequency-selective Surfaces Using Stepped Impedance Resonators for Spurious Shift Control
2025-09-27
PIER M
Vol. 135, 45-54, 2025
download: 99
Evaluation of Complex Permittivity for Composite Dispersive Media Including Concrete
Keito Matsuoka, Ryosuke Ozaki and Tsuneki Yamasaki
In this paper, the dielectric constant distribution of concrete was determined, which is consistent with the experimental values, and the complex dielectric constants obtained were evaluated. Numerical results are given by resulting complex dielectric constant distributions of four types, the time response waveforms and frequency spectra of a composite dispersive medium consisting of concrete using these dielectric constant distributions, and the time response waveforms and frequency spectra separated by each reflection component. A fast inversion of the Laplace transform method was used for the numerical analysis. Consequently, we were able to clarify the dielectric constant distribution suitable for the analysis by using these time response waveforms and frequency spectra.
Evaluation of Complex Permittivity for Composite Dispersive Media Including Concrete
2025-09-22
PIER M
Vol. 135, 34-44, 2025
download: 119
Spin Spherical Harmonics for the Analysis of Antenna Electromagnetic Fields
Alice Quennelle, Alexandre Chabory and Romain Contreres
Spherical harmonics are classical analysis tools in many science and engineering domains. For analyzing the electromagnetic fields of antennas in the frequency domain, the mostly used formulation is the one proposed by Hansen. This article proposes an alternative solution, relying on spin spherical harmonics. On a sphere, the tangential components of the electric and magnetic fields are represented by means of harmonics of spin ±1. Then new closed-form relations are established between the spin spherical harmonics and the ones formulated by Hansen. A sampling theorem and fast transforms that are consistent with spin spherical harmonics are used. The radiations of spin spherical harmonics of order 1 are related to elementary dipoles and Huygens sources in circular polarization. Finally, numerical experiments are performed with a horn antenna and a GNSS antenna installed on an aircraft. They show that a very large radiating system with a band-limit of 2048 can be efficiently analyzed by means of fast spin spherical harmonic transforms, with a computation time of 2 minutes, approximately.
Spin Spherical Harmonics for the Analysis of Antenna Electromagnetic Fields
2025-09-18
PIER M
Vol. 135, 22-33, 2025
download: 220
Structure-Preserving Discretization of the Magnetic Diffusion Equation Using DEC and FEEC
Lukas Schöppner and Matthias Friedrich
This paper presents a numerical approach for solving the magnetic diffusion equation using structure-preserving discretization methods, like Discrete Exterior Calculus (DEC) and Finite Element Exterior Calculus (FEEC). A detailed derivation of the DEC operators is provided, also their geometric foundation and relevance for discretizing differential forms on meshes. Furthermore, the paper includes an explicit introduction to the finite element exterior calculus framework, with a concise overview of the underlying functional spaces. The proposed formulations aim to preserve the topological and metric structure inherent in Maxwell's equation system. Numerical examples illustrate the stability and convergence of both methods, while also comparing their treatment of boundary conditions and discrete Hodge star construction which makes DEC and FEEC solvers spurious free and efficient useful for complex geometries.
Structure-preserving Discretization of the Magnetic Diffusion Equation Using DEC and FEEC
2025-09-14
PIER M
Vol. 135, 11-21, 2025
download: 139
Raman and FTIR Fingerprint Spectra of Blood and Bronchoalveolar Lavage Fluid for AI-Based Classification of Severe Pneumonia
Sailing He, Jialun Li, Anqi Yang, Chenhui Wang, Chuan Zhang, Xinyue Li, Ke Cui, Youzu Xu, Julian Evans and Yinghe Xu
Severe pneumonia poses a significant threat to public health. Delayed diagnosis is a core challenge in treatment. This study uses two rapid, low-cost spectroscopic fingerprinting techniques - Raman spectroscopy and attenuated total reflectance Fourier transform infrared (ATR-FTIR) absorption spectroscopy - to analyze biofluids such as blood and bronchoalveolar lavage fluid (BALF). In contrast to our earlier work which combined infrared spectra with clinical biochemical test results, this paper focuses solely on the spectral data to validate a fast and label-free diagnostic method. We used a spectral transformer network (STNetwork) to perform AI-based classification of severe pneumonia from the spectral fingerprints of blood and BALF. While both modalities are effective, FTIR spectroscopy exhibits superior diagnostic precision (97.78% test accuracy) and stability (SD < 0.0139) for blood samples. BALF offers a unique window into the local lung microenvironment, and both metabolomic analysis and spectral fingerprint classification were performed. The classification results for BALF Raman spectra (enhanced with surface-enhanced Raman spectroscopy) gave a training accuracy of 96.71%±1.86% and a testing accuracy of 90.62%±3.95%, better than the classification results for BALF FTIR spectra. The present study provides a reliable technical foundation for developing rapid and high-accuracy screening solutions for severe pneumonia.
Raman and FTIR Fingerprint Spectra of Blood and Bronchoalveolar Lavage Fluid for AI-based Classification of Severe Pneumonia
2025-09-11
PIER M
Vol. 135, 1-10, 2025
download: 98
Design of a Miniaturized Dual Notched UWB Bandpass Filter Using Meander Resonator with C-Band Interference Suppression Capability
Piali Chakraborty, Jyoti Ranjan Panda, Arindam Deb and Jibendu Sekhar Roy
This article proposes a miniaturized dual notched ultrawide bandpass filter (BPF) for ultra-wideband (UWB) indoor applications. The initial operational spectrum recognition is realized through the resonances of multiple mode resonator (MMR). Then both the passband and stopband characteristics are improved substantially by mounting distinctly shaped meander resonators cascaded with open loop ring resonator on the MMR. Further, the interdigital coupled lines are also meandered to contribute in filter size reduction along with tightening the coupling between the effective filter structure and input/output ports. The elimination of interfering signals within the passband caused by C-band satellite downlink and fixed satellite service uplink is facilitated by two sharp notches at 3.76 GHz and 6.82 GHz frequencies. Concurrently, this miniaturized filter is also characterized by its wide passband of 6.42 GHz with fractional bandwidth (FBW) 110.88%, good selectivity of 0.85, minimal insertion loss differing between 0.44 dB and 0.85 dB, wide upper stopband of 5.11 GHz, etc. ensuring its suitability as a practical UWB filter. The design is fabricated and measured to compare with the simulated outcomes and validated by the obtained resemblance between the measured and simulated filter outputs.
Design of a Miniaturized Dual Notched UWB Bandpass Filter Using Meander Resonator with C-band Interference Suppression Capability