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Ground-to-UAV and RIS-assisted UAV-to-Ground Communication Under Channel Aging: Statistical Characterization and Outage Performance

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IEEE Transactions on Communications 2025年

作者： Luan Nguyen, Thanh Kaddoum, Georges Nhu Do, Tri Haas, Zygmunt J. Université du Québec MontréalQCH3C 1K3 Canada Electrical Engineering Department Polytechnique Montréal MontréalQC Canada Department of Computer Science University of Texas DallasTX75080 United States The School of Electrical and Computer Engineering Cornell University IthacaNY14853 United States

This paper studies the statistical characterization of ground-to-air (G2A) and reconfigurable intelligent surface (RIS)assisted air-to-ground (A2G) communications in RIS-assisted UAV networks under the impact of channel aging. A comprehensive channel model is presented, which incorporates the time-varying fading, three-dimensional (3D) mobility, Doppler shifts, and the effects of channel aging on array antenna structures. We provide analytical expressions for the G2A signal-to-noise ratio (SNR) probability density function (PDF) and the corresponding cumulative distribution function (CDF), demonstrating that the G2A SNR follows a mixture of noncentral χ2 distributions. The A2G communication is characterized under RIS arbitrary phase-shift configurations, showing that the A2G SNR can be represented as the product of two correlated noncentral χ2 random variables (RVs). Additionally, we present the PDF and the CDF of the product of two independently distributed noncentral χ2 RVs, which accurately characterize the A2G SNR’s distribution. Our paper confirms the effectiveness of RIS-assisted communication in mitigating channel aging effects within the coherence time. Finally, we propose an adaptive spectral efficiency method that ensures consistent system performance and satisfactory outage levels when the UAV and the ground user equipment are in motion. © 1972-2012 IEEE.

关键词： Distribution functions

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A More Generalized Scattering Matrix for the Analysis of Active Modulated Metasurfaces

A More Generalized Scattering Matrix for the Analysis of Act...

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Conference on Millimeter - Wave and Terahertz Technologies (MMWaTT)

作者： M. S. Khatami L. Yousefi M. Dehmollaian School of Electrical and Computer Engineering University of Tehran Tehran Iran Department of Electrical Engineering Polytechnique Montral Montreal Canada

Recently, spatio-temporally modulated metasurfaces have received considerable attention among research groups around the world due to their extraordinary properties and interesting applications. That makes having a tool to model these structures and predict their behavior accurately, important and even vital for many applications. In this paper, a new analytical model is developed which is able to model a large group of spatio-temporally modulated metasurfaces. In this extension, a time-varying impedance boundary condition in conjunction with novel generalized scattering parameters is proposed and utilized. The developed analytical model is then validated through comparison with the results reported in previous works.

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Closed-Form Approximations for RF Radiation from Implantable Medical Devices

Closed-Form Approximations for RF Radiation from Implantable...

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European Conference on Antennas and Propagation, EuCAP

作者： Mingxiang Gao Zvonimir Sipus Myles Capstick Niels Kuster Anja K. Skrivervik Microwaves and Antennas Group Ecole Polytechnique Federale de Lausanne Lausanne Switzerland Foundation for Research on Information Technologies in Society (IT'IS) Zurich Switzerland Faculty of Electrical Engineering and Computing University of Zagreb Zagreb Croatia Department of Information Technology and Electrical Engineering ETH Zurich Zurich Switzerland

ISBN: (数字)9788831299107

ISBN: (纸本)9798350366327

The radio frequency (RF) performance of implantable antennas is significantly affected by the lossy biological tissues surrounding the implant. This paper introduces an an-alytical method for assessing the gain and radiation patterns of implantable antennas using planar body models, which are particularly suitable for large host bodies like the human body. The closed-form expressions derived in this method reveal that the antenna gain primarily depends on a few key parameters such as host body complex permittivity, implantation depth, operating frequency, and encapsulation dimensions. A numerical case study featuring an ingestible smart capsule within an anatomical human body model demonstrates the practical application of this method, offering a streamlined approach for assessing RF performance in the early stages of implantable antenna design.

关键词： Radio frequency Encapsulation Wireless communication Performance evaluation Medical devices Closed-form solutions Antenna theory Numerical models Permittivity Antenna radiation patterns

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Going beyond compositions, DDPMs can produce zero-shot interpolations 24

Going beyond compositions, DDPMs can produce zero-shot inter...

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Proceedings of the 41st International Conference on Machine Learning

作者： Justin Deschenaux Igor Krawczuk Grigorios G. Chrysos Volkan Cevher Department of Computer Science École Polytechnique Fédérale de Lausanne (EPFL) Lausanne Switzerland LIONS École Polytechnique Fédérale de Lausanne (EPFL) Lausanne Switzerland Department of Electrical and Computer Engineering University of Wisconsin-Madison and LIONS École Polytechnique Fédérale de Lausanne (EPFL) Lausanne Switzerland

Denoising Diffusion Probabilistic Models (DDPMs) exhibit remarkable capabilities in image generation, with studies suggesting that they can generalize by composing latent factors learned from the training data. In this work, we go further and study DDPMs trained on strictly separate subsets of the data distribution with large gaps on the support of the latent factors. We show that such a model can effectively generate images in the unexplored, intermediate regions of the distribution. For instance, when trained on clearly smiling and non-smiling faces, we demonstrate a sampling procedure which can generate slightly smiling faces without reference images (zero-shot interpolation). We replicate these findings for other attributes as well as other datasets. Our code is available on GitHub.

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High-Q microring resonator on hybrid Si3N4/ScAlN platform

High-Q microring resonator on hybrid Si3N4/ScAlN platform

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IEEE Photonics Conference (IPC)

作者： Jiangnan Liu Shuai Liu Abdur-Raheem Al-Hallak Pierre-Luc Thériault You Wu Stéphane Kéna-Cohen Mack Kira Moe Soltani Zheshen Zhang Zetian Mi Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA Department of Engineering Physics École Polytechnique de Montréal Montréal Canada Raytheon BBN Technologies Cambridge USA

A high-Q microring resonator based on a hybrid structure of ScAlN integrated with Si 3 N 4 is reported with intrinsic Q-factor up to 1.4 × 10 5 .

ISBN: (数字)9798350361957

ISBN: (纸本)9798350361964

A high-Q microring resonator based on a hybrid structure of ScAlN integrated with Si 3 N 4 is reported with intrinsic Q-factor up to 1.4 × 10 5 .

关键词： Q-factor Performance evaluation Optical resonators Resonant frequency Optical variables measurement Optics Resonance Optimization Quantum communication Photonics

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Interpolation-Free Deep Learning for Meteorological Downscaling on Unaligned Grids Across Multiple Domains with Application to Wind Power

arXiv

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arXiv 2024年

作者： Giroux, Jean-Sébastien Breton, Simon-Philippe Carreau, Julie National Prediction Development Environment and Climate Change Canada Dorval Canada Department of Computer and Electrical Engineering Sherbrooke University Sherbrooke Canada Department of Mathematics and Industrial Engineering Polytechnique Montréal Montréal Canada

As climate change intensifies, the shift to cleaner energy sources becomes increasingly urgent. With wind energy production set to accelerate, reliable wind probabilistic forecasts are essential to ensure its efficient use. However, since numerical weather prediction models are computationally expensive, probabilistic forecasts are produced at resolutions too coarse to capture all mesoscale wind behaviors. Statistical downscaling, typically applied to enchance the resolution of climate model simulations, presents a viable solution with lower computational costs by learning a mapping from low-resolution (LR) variables to high-resolution (HR) meteorological variables. Leveraging deep learning, we evaluate a downscaling model based on a state-of-the-art U-Net architecture, applied to an ensemble member from a coarse-scale probabilistic forecast of wind velocity. The architecture is modified to incorporate (1) a learned grid alignment strategy to resolve LR-HR grid mismatches and (2) a processing module for multi-level atmospheric predictors. To extend the downscaling model's applicability from fixed spatial domains to the entire Canadian region, we assess a transfer learning approach. Our results show that the learned grid alignment strategy performs as well as conventional pre-processing interpolation steps and that LR wind speed at multiple levels is sufficient as a predictor, enabling a more compact architecture. Additionally, they suggest that extending to new spatial domains using transfer learning is promising, and that downscaled wind velocities demonstrate potential in improving the detection of wind power ramps, a critical phenomenon for wind energy. © 2024, CC BY-NC-SA.

关键词： Wind forecasting

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Effect of Transducer Position on Droplet Coalescence

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Procedia computer Science 2023年 224卷 349-356页

作者： Ilyes Sayad Nabil Kharoua Didarul Islam Mahmoud Meribout Lyes Khezzar Mechanical Engineering Department Ecole Nationale Polytechnique de Constantine BP 75 A Nouvelle ville RP Constantine Algeria Mechanical Engineering Department Khalifa University of Science & Technology Abu Dhabi 127788 United Arab Emirates Electrical Engineering & Computer Science Department Khalifa University of Science & Technology Abu Dhabi PO. Box 2533 United Arab Emirates

The increasing demands for fossil fuels and the current geopolitical context have driven petroleum producers to optimize production processes and reduce their carbon footprint. This study investigates the effects of ultrasounds on droplet coalescence. Using COMSOL Multiphysics, simulations were conducted to explore the influence of transducer position on droplet coalescence. The effects of ultrasounds on water droplets coalescing in oil under different flow regimes were examined, considering a 2D computational domain divided into three parts representing the transducer, oil pool, and water droplets. The results demonstrate that switching the transducer from the side to the bottom or top significantly reduces coalescence time, with the top position yielding the shortest time. Droplets exhibit motion and deformation when the transducer is placed on the bottom or top, while no noticeable motion is observed when placed on the side. This motion induces relative deformation of the resulting droplet. Moreover, as the continuous oil phase moves with a certain velocity, whether in laminar or turbulent flow, more significant deformation occurs. Overall, placing the transducer on the top consistently yields the lowest coalescence time.

关键词： De-emulsification Ultrasounds Droplets Coalescence COMSOL

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Advanced Simulation and Design Methodology of Josephson Traveling-Wave Parametric Amplifiers (JTWPA) for Quantum Electronics Applications

Advanced Simulation and Design Methodology of Josephson Trav...

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Innovative Research in Applied Science, engineering and Technology (IRASET),Conference on

作者： Aziz Oukaira Yvon Savaria Mounir Boukadoum Ahmed Lakhssassi Department of Engineering and Computer Science University of Québec in Outaouais (UQO) Gatineau QC Canada Department of Electrical Engineering Polytechnique Montreal Montreal QC Canada Department of Computer Science University of Quebec in Montreal (UQAM) Montreal QC Canada Department of Engineering and Computer Science (UQO) University of Québec in Outaouais Gatineau QC Canada

ISBN: (数字)9798350309508

ISBN: (纸本)9798350309515

This paper examines the use of a quantum electronics Josephson Traveling-Wave Parametric Amplifier (JTWPA). The JTWPA presents distinctive features for amplifying quantum signals through the nonlinear Josephson junction, influenced by quantum effects at microwave energy scales. The study focuses on characterizing this quantum effects-based parametric amplification, offering perspectives in communication and information processing technologies. The results, obtained with the Advanced Design System (ADS) pathWave tool suggest promising applications of JTWPA, paving the way for significant advances in quantum electronics. Notably, the findings indicate that at a fixed frequency of 4 GHz and a constant pump current of 1.85 µA, the transmission efficiency of JTWPA decreases by 32% when exporting the design as layouts using the High-Frequency Structural Simulator (HFSS). Consequently, optimization with ADS emerges as a crucial step to assess transmission and information processing before the physical implementation of the JTWPA design.

关键词： Performance evaluation Degradation Design methodology Layout Information processing Microwave communication Josephson junctions

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Statistical Characterization of RIS-Assisted UAV Communications in Terrestrial and Non-Terrestrial Networks Under Channel Aging

Statistical Characterization of RIS-Assisted UAV Communicati...

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IEEE International Conference on Communications (ICC)

作者： Thanh Luan Nguyen Georges Kaddoum Tri Nhu Do Zygmunt J. Haas Department of Electrical Engineering École de Technologie Supérieure (ETS) Montréal QC Canada Artificial Intelligence & Cyber Systems Research Center Lebanese American University Electrical Engineering Department Polytechnique Montréal Montréal QC Canada Department of Computer Science University of Texas at Dallas TX USA School of Electrical and Computer Engineering Cornell University Ithaca NY USA

ISBN: (数字)9781728190549

ISBN: (纸本)9781728190556

This paper studies the statistical characterization of ground-to-air (G2A) and reconfigurable intelligent surface (RIS)-assisted air-to-ground (A2G) communications with unmanned aerial vehicles (UAVs) in terrestrial and non-terrestrial networks under the impact of channel aging. We first model the G2A and A2G signal-to-noise ratios (SNRs) as non-central complex Gaussian quadratic random variables (RVs) and derive their exact probability density functions, offering a unique characterization for the A2G SNR as the product of two scaled non-central chi-square RVs. Moreover, we also find that, for a large number of RIS elements, the RIS-assisted A2G channel can be characterized as a single Rician fading channel. Our results reveal the presence of channel hardening in A2G communication under low UAV speeds, where we derive the maximum target spectral efficiency (SE) for a system to maintain a consistent required outage level. Meanwhile, high UAV speeds, exceeding 50 m/s, lead to a significant performance degradation, which cannot be mitigated by increasing the number of RIS elements.

关键词： Spectral efficiency Rician channels Reconfigurable intelligent surfaces Aging Probability density function Autonomous aerial vehicles Air to ground communication

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Performance Analysis of Economic Model Predictive Control on a Solar-Powered Direct Contact Membrane Distillation System

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IFAC-PapersOnLine 2022年第33期55卷 13-19页

作者： Hichem Bessafa Ghania Khodja Chakir Messaoud Taous-Meriem Laleg-Kirati Electrical and Computer Engineering Program. Computer Electrical and Mathematical Science and Engineering (CEMSE) division. King Abdullah University of Science and Technology (KAUST) Ecole Polytechnique of Algiers Algeria National Institute for Research in Digital Science and Technology (INRIA) Paris-Saclay France

This paper proposes an economic model predictive control (EMPC) design for a Direct Contact Membrane Distillation powered by a solar collector system which aims at enhancing its economical performances. A differential algebraic equations-based model is used for the design of the EMPC control. Moreover, a nonlinear observer is developed for the estimation of the unmeasured state. A neural network is proposed to predict the unknown solar irradiance for future horizon where a solar model provides temperature predictions. The proposed control design has been validated in simulation using data provided by a partial differential equation-based model mimicking the real plant.

关键词： Direct contact membrane distillation Economic model predictive control differential algebraic equations nonlinear observer Long-short term memory neural network

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