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Power engineering Conference (SAUPEC), Southern African Universities

作者： Luthando Nkalitshana Senthil Krishnamurthy Haltor Mataifa Department of Electrical Electronics and Computer Engineering Centre for Substation Automation and Energy Management Systems (CSAEMS) Center for Intelligent Systems and Emerging Technologies (CSIET) Cape Peninsula University of Technology Bellville South Africa

ISBN: (数字)9798331535162

ISBN: (纸本)9798331535179

The research investigates the laboratory-scale setup and functional testing of distance protection techniques for the Transnet traction system. The Transnet network, which powers South Africa's railway system, requires a strong protection mechanism to assure the safety and dependability of the electrical systems that power locomotives. Distance protection, essential in securing high-voltage transmission networks, is critical to detecting faults, isolating affected portions, and minimizing system interruptions. In this study, a simulation environment was created to simulate the features of the Transnet traction system, including traction substations, overhead power lines, and associated equipment. A lab-scale model was developed utilizing protection functional simulation to simulate real-time fault situations and evaluate the distance protection relay's response under different fault conditions. The performance and efficacy of the protection mechanism were assessed by varying key factors such as fault impedance, fault location, and fault types.

关键词： Rails Substations Simulation Reliability engineering Stability analysis Software Real-time systems Protection Load flow Testing

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Individual Confidential Computing of Polynomials over Non-Uniform Information

arXiv

引用

arXiv 2025年

作者： Tarnopolsky, Saar Deng, Zirui Ramkumar, Vinayak Raviv, Netanel Cohen, Alejandro Faculty of ECE Technion Israel Department of Computer Science and Engineering Washington University in St. Louis St. Louis United States Department of Electrical Engineering–Systems Tel Aviv University Israel

In this paper, we address the problem of secure distributed computation in scenarios where user data is not uniformly distributed, extending existing frameworks that assume uniformity, an assumption that is challenging to enforce in data for computation. Motivated by the pervasive reliance on single service providers for data storage and computation, we propose a privacy-preserving scheme that achieves information-theoretic security guarantees for computing polynomials over non-uniform data distributions. Our framework builds upon the concept of perfect subset privacy and employs linear hashing techniques to transform non-uniform data into approximately uniform distributions, enabling robust and secure computation. We derive leakage bounds and demonstrate that information leakage of any subset of user data to untrusted service providers, i.e., not only to colluding workers but also (and more importantly) to the admin, remains negligible under the proposed scheme. © 2025, CC BY.

关键词： Information leakage

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Optical constants and critical-point transitions in biaxially tensile-strained epitaxial thin films of germanium

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Physical Review Applied 2025年第2期23卷 024037-024037页

作者： Rutwik Joshi Nina Hong Neha Singh Muntasir Mahdi Mantu K. Hudait Advanced Devices & Sustainable Energy Laboratory (ADSEL) Bradley Department of Electrical and Computer Engineering Virginia Tech Blacksburg Virginia 24061 USA J.A. Woollam Co. Inc. Lincoln Nebraska 68508 USA

We present the optical properties of epitaxial germanium (Ge) thin films as a function of tensile strain from 0% to 1.96%, measured using variable-angle spectroscopic ellipsometry in the energy range of 0.5–4.1 eV. The band structure of unstrained Ge is modified using epitaxial tensile strain imparted by the underlying compositionally controlled InxGa1−xAs strain template. The degeneracy of Ge’s light-hole (LH) and heavy-hole (HH) bands near the Γ point is lifted due to tensile strain while the Γ and L valleys descend. Such changes in the band structure impact the optical properties of tensile-strained Ge, such as the dielectric constant, refractive index, and absorption coefficient. At the Γ point, it is noticed that the absorption coefficient gradually increases with tensile strain, indicating a shift in the effective band edge of Ge. Further, it is observed that the indirect transitions are dominated by L-LH, whereas the direct transitions are contributed from the Γ-LH as well as the Γ-HH due to the interplay between the transition energy and joint density of states. In addition, the tensile strain is seen to affect the band structure at different regions in the Brillouin zone (BZ) resulting in the movement of the critical points (CPs) to lower energy in the optical spectrum. The E1 and E1+ Δ1 CPs in tensile-strained Ge are redshifted compared with unstrained Ge. The observed movement of the E1, and E0 CP peaks is in close agreement with the first principles calculated band structure. Further, the apparent value of the E0 spin-orbit (SO) energy, Δ0 is seen to decrease with increasing tensile strain at the Γ point. Interestingly, the E1 SO energy, Δ1 at the Λ direction in the BZ remains constant, indicating a very low shear deformation-related shift in the band structure due to biaxial tensile strain. As tensile-strained Ge thin films have a wide range of potential applications in electronics, sensing, and photonics, further understanding of tensile strain in Ge a

关键词： Refractive index

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IEC61850 GOOSE message application for a power transformer voltage control

IEC61850 GOOSE message application for a power transformer v...

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Power engineering Conference (SAUPEC), Southern African Universities

作者： Joniff Wellen Senthil Krishnamurthy Mukovhe Ratshitanga Department of Electrical Electronics and Computer Engineering Centre for Substation Automation and Energy Management Systems (CSAEMS) Centre for Intelligent Systems and Emerging Technologies (CSIET) Cape Peninsula University of Technology Bellville South Africa

ISBN: (数字)9798331535162

ISBN: (纸本)9798331535179

Voltage regulation of power transformers is critical to controlling and maintaining system voltage levels in the electrical transmission and distribution network system. It is vital to keep the transmission and distribution network's voltage levels within a specified range and to avoid voltage levels from fluctuating outside of the predetermined range of allowed tolerance levels. Two SEL-2414 IEDs were employed in this study to perform the voltage control function of the parallel power transformers using a master-follower control scheme. The automatic tap changers that execute this voltage regulating function incorporate the IEC61850 GOOSE message application as the communication protocol. The paper demonstrates the control function, a hardware-in-the-loop simulation in a closed-loop simulation using Real Time Digital Simulator (RTDS), and the two transformer tap changer IEDs SEL-2414 were utilized for lab-scale implementation and validating the simulation results.

关键词： Substations Protocols Hardware-in-the-loop simulation Reliability engineering Real-time systems Power transformers Tap changers Voltage control Protection Remote monitoring

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Improved High-Speed Thermal Analysis Based on Two-Step Simulation for High-Frequency Transformers

Improved High-Speed Thermal Analysis Based on Two-Step Simul...

引用

Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC)

作者： Zheyuan Yi Kai Sun Qiang Li Zengyang Liu Department of Electrical Engineering State Key Laboratory of Power System Tsinghua University Beijing China Delta Electronics Shanghai Co. Ltd. Shanghai China The Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State Center for Power Electronics Systems University Blacksburg Virginia USA

ISBN: (数字)9798331516116

ISBN: (纸本)9798331516123

Thermal analysis is a crucial and time-consuming step in the optimization design process of high-frequency transformers (HFTs). This paper proposes an improved thermal analysis method based on heat dissipation-conduction two-step simulation, significantly reducing the computation time while ensuring the accuracy of thermal analysis. Simulation results validate the accuracy and of the proposed method and demonstrate that the proposed method saves 82% of computation time for a single thermal analysis case compared to direct CFD. Experimental results further verify the accuracy of the proposed method. An exemplary application of the proposed method in the optimization design of the HFT illustrates a 98% reduction in computation time for thermal analysis during the optimization process.

关键词： Heating systems Temperature distribution Accuracy Simulation Computational modeling Thermal analysis High-frequency transformers Optimization Surface treatment Heat transfer

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A Novel Circularly Polarized Filtering Reflectarray by Manipulating the Multimode Reflective Phase of Orthogonal Polarizations

引用

IEEE Transactions on Antennas and Propagation 2025年

作者： Fang, Chang Zhang, Xiao Li, Yin Zhu, Lei Wong, Sai-Wai Quan, Zhi China Shenzhen University College of Electronics and Information Engineering Shenzhen518060 China Peng Cheng Laboratory Shenzhen518038 China University of Macau Faculty of Science and Technology Department of Electrical and Computer Engineering Macau China

This paper presents a novel design methodology for circularly polarized (CP) filtering reflectarray (RA). Unlike conventional filtering techniques based on magnitude response, the proposed filtering RA solely manipulates the phase responses of the reflected wave under the total reflection condition. An isosceles triangle patch radiator loaded with slots is employed as the unit cell. Two sets of orthogonal resonant modes of the triangular patch are exploited to produce a phase difference between the u- and v-polarized components. By adopting slot loading, first- and third-order resonant states are induced in the two orthogonal directions. Next, the phase difference is fully controlled by adjusting the slope of the reflection phase. In the passband, the phase difference is maintained at 180°, while outside the band, it rapidly rolls down (up) to 0° (360°), enabling steep band edges. Finally, a CP filtering RA using the optimized element is constructed for the first time, which verifies the validity of the proposed method. The fabricated RA exhibits satisfactory performance, including a 3-dB gain bandwidth of 25.7%, 3-dB axial ratio (AR) bandwidth of 29.8%, and the out-of-band suppression levels of 33.5 dB (22.8 dB) in the low (high) frequency band. © 1963-2012 IEEE.

关键词： Circular polarization

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Hybrid Routing in VANETs Using OLSR and Q-Learning for Enhanced Performance

Hybrid Routing in VANETs Using OLSR and Q-Learning for Enhan...

引用

IEEE SSD International Multi-Conference on systems, Signals and Devices

作者： Wafa Akermi Nouha Alyaoui Awatef Benfradj Guiloufi Karim Chabir Computer Science and Telecommunications Department Higher Institute of Applied Science and Technology Gafsa University Gafsa Tunisia Laboratory of Modeling Analysis and Control of Systems (MACS) National Engineering School of Gabes (ENIG) Gabes University Gabes Tunisia Departement of Computer Engineering College of Computer Qassim University Buraidh Saudi Ababia

ISBN: (数字)9798331542726

ISBN: (纸本)9798331542733

High node mobility, rapid topology changes provide specific challenges for vehicular ad hoc networks (VANETs), which have an immediate impact on the routing protocols' performance. Traditional approaches, like the Optimized Link State Routing (OLSR) protocol, provide proactive route management but fail to fully account for critical dynamic parameters like link stability, relative vehicle speed, node distance, and bandwidth availability. This work proposes a hybrid method combining OLSR with Q-learning to facilitate real-time adaptive routing. The model leverages dynamic metrics to proactively evaluate links while employing Q-learning to optimize routing decisions based on rewards computed from performance factors like delay, packet loss rate, and link duration. Simulation results demonstrate that our approach significantly outperforms classic OLSR. The improvements include reduced packet loss rates, increased average throughput, lower average latency, and a reduction in control overhead. These findings confirm that integrating dynamic metrics and adaptive learning effectively addresses the challenges posed by VANETs.

关键词： Q-learning Simulation Vehicular ad hoc networks Packet loss Routing Throughput Routing protocols Stability analysis Topology Vehicle dynamics

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Advancing Lymphoma Diagnosis in Histopathology Image Classification Using Multi Deep Learning Models

Iraqi Journal for Computer Science and Mathematics

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Iraqi Journal for computer Science and Mathematics 2025年第2期6卷 180-187页

作者： Elaraby, Ahmed Nechaevskiy, Andrey Saad, Aymen Department of Computer Science Faculty of Computers and Information South Valley University Qena83523 Egypt Cairo Egypt Meshcheryakov Laboratory of Information Technologies Joint Institute for Nuclear Research Joliot-Curie 6 Dubna141980 Russia Department of Information Technology Management Technical College Al-Furat Al-Awsat Technical University Kufa54003 Iraq School of Electrical Engineering Universiti Teknologi Malaysia Johor Skudai81310 UTM Malaysia

Deep learning’s rapid development is generating significant interest in its potential to improve medical imaging. It has shown promising results in detecting malignant lymphoma in histopathology medical images. Image classification methods are widely used to aid in making diagnoses from medical images. In recent years, deep learning methods have achieved high performance in detecting malignant lymphoma in histopathology images. This study proposes a novel approach to improving lymphoma diagnosis in histopathology images called the Lightweight Convolutional Neural Network (LWCNN). The proposed LWCNN model comprises multiple deep learning architectures, including a convolutional neural network (CNN) that has been trained to classify lymphoma subtypes based on histopathology images using ResNet50 and MobileNetV2. The LWCNN model aggregates the predictions of disparate architectures to arrive at a definitive diagnosis, leveraging the unique capabilities of each. A comprehensive dataset of annotated lymphoma histopathology images was assembled for the purpose of training the multi-deep learning model. To ensure a representative and diverse training set, the dataset was meticulously curated to encompass various subtypes of lymphoma. Performance evaluation of the proposed deep learning model for lymphoma classification using standard metrics revealed the following accuracies: LWCNN (97.34% training, 86.71% testing), ResNet50 (88.76% training, 86.37% testing), and MobileNetV2 (88.47% training, 86.60% testing). These results indicate that the LWCNN model significantly surpasses existing approaches in diagnostic accuracy. © 2025 The Author(s).

关键词： Photointerpretation

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Joint Beamforming and Power Allocation Design for Wirelessly Charged Unmanned Inspecting Vehicles in Power Transmission systems

IEEE Transactions on Green Communications and Networking

引用

IEEE Transactions on Green Communications and Networking 2025年

作者： Huang, Yingjie Abdelhady, Amr M. Wang, Qianggang Ye, Jia Chi, Yuan Eltawil, Ahmed M. El-Sherif, Amr A. ElBatt, Tamer Chongqing University State Key Laboratory of Power Transmission Equipment Technology School of Electrical Engineering Chongqing400044 China King Abdullah University of Science and Technology Computer Electrical and Mathematical Science and Engineering Division Province Makkah23955-6900 Saudi Arabia Electronics and Communications Department Egypt University of Informatics Cairo Governorate Egypt Department of Computer Science and Engineering The American University Cairo Governorate Cairo Egypt

The rapid development of the smart grid has intensified research efforts towards automating power transmission system inspections using unmanned intelligent vehicles (UIVs). A major challenge hindering their large-scale deployment is the short operational endurance of these vehicles. This paper addresses this limitation by proposing the use of an energy transmitter (ET) and a reconfigurable intelligent surface for wirelessly charging the vehicles through radio frequency (RF) signals. Additionally, we tackle the nonlinearity of RF-to-direct current (DC) conversion, which shows efficiency saturation at high power levels, by introducing a novel power-splitting (PS) energy harvesting (EH) receiver architecture in the inspection vehicles. The inspection tasks are divided into multiple time slots, and a power transfer efficiency (PTE) maximization problem is formulated to jointly optimize the beamforming design at both the transmitter and the RIS, as well as the transmit power allocation and receiving power splitter settings for each time slot. This approach aims to meet the energy requirements of the unmanned inspection vehicles while adhering to the total available power constraint at the ET. To solve the non-convex PTE maximization problem, we propose an efficient solution utilizing alternating optimization, the Dinkelbach’s method, and successive convex approximation, considering the unique properties of channel structure and finite phase resolution. Numerical results demonstrate that our proposed system and design significantly extend the lifespan of inspection vehicles and achieve high energy efficiency in a low-complexity manner. © 2017 IEEE.

关键词： Inductive power transmission

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Efficient Coordination and Synchronization of Multi-Robot systems Under Recurring Linear Temporal Logic

arXiv

引用

arXiv 2025年

作者： Peron, Davide Fernandez-Ayala, Victor Nan Vlahakis, Eleftherios E. Dimarogonas, Dimos V. Department of Information Engineering University of Padova Padova35122 Italy Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm10044 Sweden

We consider multi-robot systems under recurring tasks formalized as linear temporal logic (LTL) specifications. To solve the planning problem efficiently, we propose a bottom-up approach combining offline plan synthesis with online coordination, dynamically adjusting plans via real-time communication. To address action delays, we introduce a synchronization mechanism ensuring coordinated task execution, leading to a multi-agent coordination and synchronization framework that is adaptable to a wide range of multi-robot applications. The software package is developed in Python and ROS2 for broad deployment. We validate our findings through lab experiments involving nine robots showing enhanced adaptability compared to previous methods. Additionally, we conduct simulations with up to ninety agents to demonstrate the reduced computational complexity and the scalability features of our work. © 2025, CC BY.

关键词： Multipurpose robots

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