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FINITE-ELEMENT ANALYSIS OF LOSSY DIELECTRIC WAVE-GUIDES

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1994年第6期42卷 1025-1031页

作者： LEE, JF Department of Electrical and Computer Engineering Worcester Polytechnic Institute Worcester MA USA

This paper presents a full-wave analysis of lossy dielectric waveguides using a hybrid vector finite element method. To avoid the occurrences of spurious modes in the formulation, edge elements and first-order nodal finite element basis functions are used to span the transverse and the z components of the electric field, respectively. Furthermore, the direct matrix solution technique with minimum degree of reordering has been combined with the modified Lanczos algorithm to solve for the resultant sparse generalized eigenmatrix equation efficiently.

关键词： Dielectric losses Finite element methods Integrated circuit modeling Integrated circuit interconnections Electromagnetic waveguides Transmission line matrix methods Frequency Maxwell equations Predictive models LAN interconnection

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Real-time Improved Nearest Level Control for Power Electronics Building Blocks in All-Electric Ship Power Systems

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IEEE Transactions on Industry Applications 2025年

作者： Moghassemi, Ali Timilsina, Laxman Rahman, S. M. Imrat Arsalan, Ali Muriithi, Grace Buraimoh, Elutunji Ozkan, Gokhan Papari, Behnaz Edrington, Christopher S. Zhang, Zheyu Chamarthi, Phani Kumar Holcombe Department of Electrical and Computer Engineering ClemsonSC29634 United States Clemson University Department of Automotive Engineering GreenvilleSC29607 United States Clemson University Dominion Energy Innovation Center North CharlestonSC29405 United States Rensselaer Polytechnic Institute Electrical Computer Systems Engineering TroyNY12180 United States Environmental Research and Innovation Department Belval Luxembourg

Power electronics building block (PEBB) concept involves integrating fundamental components into functional blocks that can be stacked, extending converter power ratings for all-electric ships (AESs). This modular approach reduces costs, size, weight, design complexity, and maintenance. PEBBs can be realized as modular multi-level converters (MMCs), which offer advantages like modularity, low switching losses, minimal voltage/current quantization, high reliability, and efficiency. However, effective switching control methods are crucial to balance capacitor voltages and suppress circulating currents. This paper proposes an improved nearest level control (NLC) method that employs smoothed trapezoidal reference signals instead of sinusoidal references, aiming to enhance capacitor voltage balancing, suppress circulating currents, and improve the output power quality of PEBBs in AESs. The proposed NLC method is analyzed in real-time for an N-level PEBB connected to an induction machine (IM) with variable speed and torque load. The real-time verification is conducted in the Typhoon HIL606 digital real-time simulator (DRTS). The results validate the feasibility and effectiveness of the proposed NLC method for a three-phase N-level PEBB concept for AESs. © 1972-2012 IEEE.

关键词： Capacitors

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ENSURING GPS NAVIGATION INTEGRITY USING RECEIVER AUTONOMOUS INTEGRITY MONITORING

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IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE 1995年第10期10卷 31-34页

作者： MICHALSON, WR Department of Electrical and Computer Engineering Worcester Polytechnic Institute Worcester MA

The many advantages of Global Positioning System (GPS) based navigation have created a tremendous amount of interest in using GPS as the primary navigation aid onboard commercial and civil aircraft. Even in the presence of Selective Availability, the accuracy of GPS is sufficient to guide aircraft point-to-point between airports without requiring other navigation aids such as VOR or DME, Unfortunately, there is a finite probability that a GPS satellite will fail, causing the transmission of potentially misleading navigation information. Thus, before GPS can be widely adopted as a navigation aid, techniques must be devised to detect any possible failures and notify the user prior to the degradation of navigation accuracy. This paper discusses the problem of detecting possible GPS satellite failures using a technique called Receiver Autonomous Integrity Monitoring (RAIM).

关键词： Global Positioning System Satellite navigation systems Aircraft navigation Clocks Equations Degradation computerized monitoring Aircraft propulsion Availability Earth

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Controlling the Growth of Cs₂PbX₄ Nanostructures Enhances the Stability of Inorganic Cesium-Based Perovskite Solar Cells for Potential Low Earth Orbit Applications

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ACS Applied Materials and Interfaces 2025年第21期17卷 31575-31591页

作者： Nigmetova, Gaukhar Yelzhanova, Zhuldyz Zhumadil, Gulzhan Parkhomenko, Hryhorii P. Tilegen, Meruyert Zhou, Xianfang Pavlenko, Vladimir Beisenbayev, Almaz Aidarkhanov, Damir Jumabekov, Askhat N. Kaikanov, Marat Pham, Tri Thanh Balanay, Mannix P. Lim, Chang-Keun Wang, Yanwei Hu, Hanlin Ng, Annie Department of Electrical and Computer Engineering School of Engineering and Digital Sciences Nazarbayev University Astana 010000 Kazakhstan Department of Chemical and Materials Engineering School of Engineering and Digital Sciences Nazarbayev University Astana 010000 Kazakhstan National Laboratory Astana Nazarbayev University Astana 010000 Kazakhstan Department of Physics School of Sciences and Humanities Nazarbayev University Astana 010000 Kazakhstan Department of Biology School of Sciences and Humanities Nazarbayev University Astana 010000 Kazakhstan Hoffman Institute of Advanced Materials Shenzhen Polytechnic University Shenzhen 518060 China Al-Farabi Kazakh National University Almaty 050040 Kazakhstan Department of Chemistry School of Sciences and Humanities Nazarbayev University Astana 010000 Kazakhstan Laboratory of Functional Nanomaterials The Institute of Combustion Problems Almaty 050009 Kazakhstan

Incorporating low-dimensional (LD) materials in perovskite solar cells (PSCs) for interfacial engineering is an effective approach to enhance device performance. However, the growth mechanisms for inorganic LD perovskite nanostructures in cesium-based systems via solution processing are underexplored. This work demonstrates the importance of controlling solvent evaporation dynamics during solution processing to modulate Cs₂PbX₄ nanomorphology. An evolution of growing Cs₂PbX₄ nanostructures is demonstrated on CsPbI₂Br thin films. Cs₂PbX₄ nanostructures at CsPbI₂Br grain boundaries introduce a passivation effect, improving interfacial quality with the hole transport layer (HTL). Systematic characterization reveals that careful engineering of LD nanostructures strongly impacts the optoelectronic properties of PSCs. Optimized CsPbI₂Br/Cs₂PbX₄ heterostructures enhance the power conversion efficiency (PCE) from an average of 10.8% to 13.5%, achieving a 25% improvement over devices without interfacial engineering. Under a 100 h photovoltaic aging test, the PCE of the control device degraded by 30.7%, whereas the CsCl-treated devices retained 98% of their PCE from the start of the measurement. Post-proton-irradiated PSCs based on Cs₂PbX₄-modified CsPbI₂Br retain up to 96% of their initial PCE of 12.2% after exposure to low Earth orbit-like conditions, maintaining a PCE of 11.7%. In contrast, the control device exhibits significant degradation, with the PCE dropping from 11.5% to 3.1%. These findings deepen our understanding of controlling the morphology of inorganic LD nanomaterials via a solution process. The promising stability of PSCs after interfacial engineering highlights their potential for robust performance under harsh conditions. © 2025 American Chemical Society.

关键词： all-inorganic perovskites interface engineering low-dimensional perovskites nanomaterials solar cells solvent evaporation space application

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Rethinking Functional Brain Connectome Analysis: Do Graph Deep Learning Models Help?

arXiv

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arXiv 2025年

作者： Han, Keqi Su, Yao He, Lifang Zhan, Liang Plis, Sergey Calhoun, Vince Yang, Carl Dept. of Computer Science Emory University AtlantaGA United States Dept. of Computer Science Worcester Polytechnic Institute WorcesterMA United States Dept. of Computer Science and Engineering Lehigh University BethlehemPA United States Dept. of Electrical and Computer Engineering Univ. of Pittsburgh PittsburghPA United States TReNDS Center GSU Georgia Tech Emory University AtlantaGA United States

Functional brain connectome is crucial for deciphering the neural mechanisms underlying cognitive functions and neurological disorders. Graph deep learning models have recently gained tremendous popularity in this field. However, their actual effectiveness in modeling the brain connectome remains unclear. In this study, we re-examine graph deep learning models based on four large-scale neuroimaging studies encompassing diverse cognitive and clinical outcomes. Surprisingly, we find that the message aggregation mechanism, a hallmark of graph deep learning models, does not help with predictive performance as typically assumed, but rather consistently degrades it. To address this issue, we propose a hybrid model combining a linear model with a graph attention network through dual pathways, achieving robust predictions and enhanced interpretability by revealing both localized and global neural connectivity patterns. Our findings urge caution in adopting complex deep learning models for functional brain connectome analysis, emphasizing the need for rigorous experimental designs to establish tangible performance gains and perhaps more importantly, to pursue improvements in model interpretability. © 2025, CC BY.

关键词： Contrastive Learning

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A Hybrid Dynamic Subarray Architecture for Efficient DOA Estimation in THz Ultra-Massive Hybrid MIMO Systems

arXiv

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arXiv 2025年

作者： Tian, Ye Ren, Jiaji Wu, Tuo Liu, Wei Yuen, Chau Debbah, Mérouane Al-Dhahir, Naofal Valenti, Matthew C. So, Hing Cheung Eldar, Yonina C. Faculty of Electrical Engineering and Computer Science Ningbo University Ningbo315211 China School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore Department of Electrical and Electronic Engineering Hong Kong Polytechnic University Kowloon Hong Kong KU 6G Research Center Department of Computer and Information Engineering Khalifa University Abu Dhabi127788 United Arab Emirates Department of Electrical and Computer Engineering The University of Texas at Dallas RichardsonTX75080 United States Lane Department of Computer Science and Electrical Engineering West Virginia University Morgantown United States Department of Electrical Engineering City University of Hong Kong Hong Kong Weizmann Institute of Science Israel

Terahertz (THz) communication combined with ultra-massive multiple-input multiple-output (UM-MIMO) technology is promising for 6G wireless systems, where fast and precise direction-of-arrival (DOA) estimation is crucial for effective beamforming. However, finding DOAs in THz UM-MIMO systems faces significant challenges: while reducing hardware complexity, the hybrid analog-digital (HAD) architecture introduces inherent difficulties in spatial information acquisition the large-scale antenna array causes significant deviations in eigenvalue decomposition results;and conventional two-dimensional DOA estimation methods incur prohibitively high computational overhead, hindering fast and accurate realization. To address these challenges, we propose a hybrid dynamic subarray (HDS) architecture that strategically divides antenna elements into subarrays, ensuring phase differences between subarrays correlate exclusively with single-dimensional DOAs. Leveraging this architectural innovation, we develop two efficient algorithms for DOA estimation: a reduced-dimension MUSIC (RD-MUSIC) algorithm that enables fast processing by correcting large-scale array estimation bias, and an improved version that further accelerates estimation by exploiting THz channel sparsity to obtain initial closed-form solutions through specialized two-RF-chain configuration. Furthermore, we develop a theoretical framework through Cramér-Rao lower bound analysis, providing fundamental insights for different HDS configurations. Extensive simulations demonstrate that our solution achieves both superior estimation accuracy and computational efficiency, making it particularly suitable for practical THz UM-MIMO systems. © 2025, CC BY.

关键词： Eigenvalues and eigenfunctions

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An Intelligent Traffic Management of Vehicles using Deep Learning Approach in Smart Cities

An Intelligent Traffic Management of Vehicles using Deep Lea...

引用

Integrated Circuits and Communication Systems (ICICACS), IEEE International Conference on

作者： Botir Elov Adilbek Dauletov Yadala Sucharitha Feruza Khalilova Mukhayyo Latipova Mukhtasarkhon Abdullayeva Computer Linguistics and Digital Technology Alisher Navo'i Tashkent State University of Uzbek Language and Literature Tashkent Uzbekistan Department of Digital Technologies Alfraganus University Tashkent Uzbekistan Department of Computer Science and Engineering VNR Vignana Jyothi Institute of Engineering and Technology Hyderabad India Department of Electrical Power Engineering Fergana Polytechnic Institute Fergana Uzbekistan

ISBN: (数字)9798331508456

ISBN: (纸本)9798331508463

Smart traffic management of automobiles has been one of the utmost sought-after issues in the academic community due to the ever-increasing pace of urbanization and civilization over the last several centuries. Vehicle dissection, traffic density appraisal, and vehicle tracing are the three main components of smart traffic management. This problem becomes more difficult to resolve when there are occlusions, background clutter, and fluctuations in traffic density. In light of this need, we explore a deeper learning approach based on R-CNN s for faster vehicle segmentation in this study. There is adaptive backdrop modeling in the computational framework. It solves problems with lighting and shadows as well. The use of topological active net deformable models allows for segmentation that is more precise. The deformations mentioned can be accomplished with the aid of topological and stretched topological active nets. Minimizing energy allows for mesh deformation. Using a tweaked version of the stretched topological active net improves the segmentation accuracy to 98.3%. The investigational findings show that this framework is better than other methods.

关键词： Deep learning Integrated circuits Deformable models Fluctuations Smart cities Deformation Communication systems Computational modeling Lighting Traffic control

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Extinguishing Real Fires by Fully Autonomous Multirotor UAVs in the MBZIRC 2020 Competition

Field Robotics

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Field Robotics 2025年 2卷 406-436页

作者： Viktor Walter Vojtěch Spurný Matěj Petrlík Tomáš Báča David Žaitlík Lyubomyr Demkiv Martin Saska Department of Cybernetics Faculty of Electrical Engineering Czech Technical University in Prague http://mrs.felk.cvut.cz Robotics Group of SoftServe Inc. and with the Institute of Computer Science and Information Technologies Lviv Polytechnic National University Ukraine

In this paper, we describe a system for combating real fires with sprayed liquid extinguishing agent using a team of multirotor UAVs. The system design relies on onboard sensors and operates without the need for human intervention throughout its complex mission, from its takeoff to landing. The core UAV platform can estimate its state, self-localize, navigate and locate and extinguishing fires. Thermal and RGB cameras are used, each with a specialized computer vision subsystem and are combined with planar LIDAR for 3D localization of fires on multistory building facades. The system conducts aerial firefighting with a software stack that addresses flight dynamics and sensor limitations and a liquid-spraying subsystem incorporating a rigidly-attached water nozzle. The approach presented in this paper was motivated by the Mohamed Bin Zayed International Robotics Challenge (MBZIRC 2020) firefighting scenario, which focused on coordinated multi-UAV teams that can autonomously combat high-rise building fires. The MBZIRC series places particular emphasis on fast and reliable deployment of robots in realistic conditions. These contests promote development of real-world applications that are greatly needed by society, but which still exceed State-of-the-Art in the robotics community. To our knowledge, our system was the only MBZIRC 2020 contender to extinguish a facade fire successfully in autonomous mode without using an RTK-GNSS system. Our approach contributed to victory in the overall competition and we have now adapted it into an industrial prototype for a firefighting UAV. A video attachment to this paper is available at http://***/fr2020firechallenge-facadefires.

关键词： Robots Buildings Autonomous aerial vehicles Location awareness Robot kinematics Inspection Navigation Cameras Monitoring Sensor systems

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QUADRATIC ASSIGNMENT PROBLEMS GENERATED WITH THE PALUBETSKIS ALGORITHM ARE DEGENERATE

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-FUNDAMENTAL THEORY AND APPLICATIONS 1994年第7期41卷 481-484页

作者： CYGANSKI, D VAZ, RF VIRBALL, VG Department of Electrical and Computer Engineering Worcester Polytechnic Institute Worcester MA USA

The quadratic assignment problem (QAP) is a combinatorial optimization problem that arises in many applications such as the allocation of processes in distributed computer systems. The QAP is NP-hard and therefore no algorithms are known for solving the QAP in polynomial time. For this reason a variety of heuristic methods have been proposed for this problem. In order to evaluate heuristics, Palubetskis proposed an algorithm that generates QAPs with known optimal solution value. We show in this paper that given a Palubetskis instance (but not its optimal value) the corresponding optimal value can be determined via a linear program, polynomial in the input data, i.e., in polynomial time. This implies that problems generated by the Palubetskis method belong to a simple and degenerate subclass of QAPs and are therefore not appropriate for algorithm testing. The proof technique suggests moreover a new lower bound for Euclidean QAPs.

关键词： Polynomials Transmission line matrix methods Cost function Distributed computing Testing Minimization Linear matrix inequalities Symmetric matrices Application software Resource management

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True and false energy-saving devices

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IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 1997年第6期33卷 1439-1443页

作者： Emanuel, AE Electrical and Computer Engineering Department Worcester Polytechnic Institute Worcester MA USA

This paper explains the mystifying performance of a nonlinear capacitance used as a passive energy-saving device (ESD), According to the law of energy conservation, such ESD's cannot improve motor efficiency, Theoretical and experimental studies prove that the bulk of the perceived ''energy savings'' is caused by the current transformers phase-angle error.

关键词： energy-saving devices power factor correction

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