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arXiv 2024年

作者： Chi, Hanbin Hu, Yueqiang Ou, Xiangnian Jiang, Yuting Yu, Dian Lou, Shaozhen Wang, Quan Xie, Qiong Qiu, Cheng-Wei Duan, Huigao National Research Center for High-Efficiency Grinding College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Greater Bay Area Institute for Innovation Hunan University Guangzhou511300 China Advanced Manufacturing Laboratory of Micro-Nano Optical Devices Shenzhen Research Institute Hunan University Shenzhen518000 China Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore

Flexible control light field across multiple parameters is the cornerstone of versatile and miniaturized optical devices. Metasurfaces, comprising subwavelength scatterers, offer a potent platform for executing such precise manipulations. However, the inherent mutual constraints between parameters of metasurfaces make it challenging for traditional approaches to achieve full-parameter control across multiple wavelengths. Here, we propose a universal end-to-end inverse design framework to directly optimize the geometric parameter layout of meta-optics based on the target functionality of full-parameter control across multiple wavelengths. This framework employs a differentiable forward simulator integrating a neural network-based dispersive full-parameter Jones matrix and Fourier propagation to facilitate gradient-based optimization. Its superiority over sequential forward designs in dual-polarization channel color holography with higher quality and tri-polarization three-dimensional color holography with higher multiplexed capacity is showcased. To highlight the universality, we further present polarized spectral multi-information processing with six arbitrary polarizations and three wavelengths. This versatile, differentiable, system-level design framework is poised to expedite the advancement of meta-optics in integrated multi-information display, imaging, and communication, extending to multimodal sensing applications. Copyright © 2024, The Authors. All rights reserved.

关键词： Polarization

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Advances of wearable silicone rubber-based triboelectric nanogenerators: from manufacturing to application

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International Journal of Extreme Manufacturing 2025年第3期 131-164页

作者： Dianlong Shen Taili Du Fangyang Dong Hu Cai Aziz Noor Xiannan Du Yongjiu Zou Chengkuo Lee Minyi Xu Dalian Key Laboratory of Marine Micro/Nano Energy and Self-Powered Systems Marine Engineering CollegeDalian Maritime University State Key Laboratory of Maritime Technology and Safety Collaborative Innovation Research Institute of Autonomous Ship Dalian Maritime University Department of Electrical and Computer Engineering National University of Singapore

Wearable bioelectronic devices are rapidly evolving towards miniaturization and multifunctionality, with remarkable features such as flexibility and comfort. However, achieving a sustainable power supply for wearable bioelectronic devices is still a great *** nanogenerators(TENGs) provide an efficient solution by converting irregular,low-frequency bioenergy from the human body into electrical energy. Beyond sustainably powering wearable bioelectronics, the harvested electrical energy also carries rich information for human body sensing. In this conversion process, the choice of material plays a crucial role in affecting the output performance of the TENGs. Among various materials, silicone rubber(SR)stands out due to its exceptional plasticity, flexibility, comfortability and other favorable properties. Moreover, with appropriate treatment, SR can achieve extreme functionalities such as high robustness, good stability, self-healing capabilities, rapid response, and more. In this review, recent advances in wearable SR-based TENGs(SR-TENGs) are systematically reviewed with a focus on their application in different parts of the human body. Given that the manufacturing method of SR-TENGs largely determines its output performance and sensitivity,this paper introduces the design of SR-TENGs, including material selection, process modulation, and structure optimization. Additionally, this article discusses the current challenges in the SR-TENG fabrication technology and potential future directions,aiming to promote the effective development of SR-TENGs in biomechanical energy harvesting and self-powered sensing applications.

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Enhanced Redundant Scheme Based on Weighted Cluster-Head Selection for Critical 6G Infrastructures

Enhanced Redundant Scheme Based on Weighted Cluster-Head Sel...

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IEEE Globecom Workshops

作者： Grace Khayat Constandinos X Mavromoustakis Andreas Pitsillides Jordi Mongay Batalla Evangelos K. Markakis Andreas Andreou Department of Computer Science Mobile Systems Laboratory (MoSys Lab) University of Nicosia Nicosia Cyprus Department of Computer Science University of Cyprus Cyprus Department of Electrical & Electronic Engineering Science University of Johannesburg Warsaw University of Technology Warsaw Poland Department of Electrical and Computer Engineering Hellenic Mediteranean University Estavromenos Heraklion Greece Department of Computer Science Research Foundation University of Nicosia and University of Nicosia Nicosia Cyprus

ISBN: (纸本)9781665459761

Flying Ad hoc Network (FANET) consists of a group of unmanned aerial vehicles (UAVs) that fulfill a certain mission in various applications. The UAV targets uploading data to the 6G networks through communication to other UAVs or to the base station. UAVs collaborate for a purpose to achieve a certain mission in a faster and more reliable way compared to a single UAV. In critical cases such as flooding or earthquakes, one or more UAVs can be non-functional thus emerging a disconnected network. One of the most reliable routing schemes is clustering which splits the network into clusters. Every cluster incorporates a cluster-head and cluster-members. The selection of the cluster-head possesses a high influence on the routing scheme’s performance as it is responsible for all intra-cluster communication. A new clustered weighted scheme with a redundant cluster-head is proposed to ensure end-to-end communication in critical 6G infrastructures. The parameters of the weighted formula used for cluster establishment and primary cluster-head selection are the distance, the performance index, the speed, and the energy. A secondary cluster-head that automatically replaces the primary cluster-head whenever it is non-functional is selected based on the link reliability. The promising results obtained from MATLAB simulation are discussed in section IV.

关键词： 6G mobile communication Base stations Conferences Earthquakes Routing Autonomous aerial vehicles Ad hoc networks

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Tunable Magnetless Optical Isolation with Twisted Weyl Semimetals

arXiv

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arXiv 2023年

作者： Chistyakov, Vladislav Asadchy, Viktar S. Fan, Shanhui Alù, Andrea Krasnok, Alex Saint-Petersburg 191002 Russia Department of Electronics and Nanoengineering Aalto University Espoo02150 Finland Ginzton Laboratory Department of Electrical Engineering Stanford University StanfordCA94305 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY United States Department of Electrical and Computer Engineering Florida International University MiamiFL33174 United States

Weyl semimetals hold great promise in revolutionizing nonreciprocal optical components due to their unique topological properties. By exhibiting nonreciprocal magneto-optical effects without necessitating an external magnetic field, these materials offer remarkable miniaturization opportunities and reduced energy consumption. However, their intrinsic topological robustness poses a challenge for applications demanding tunability. In this work, we introduce an innovative approach to enhance the tunability of their response, utilizing multilayered configurations of twisted anisotropic Weyl semimetals. Our design enables controlled and reversible isolation by adjusting the twist angle between the anisotropic layers. When implemented in the Faraday geometry within the mid-IR frequency range, our design delivers impressive isolation, exceeding 50 dB, while maintaining a minimal insertion loss of just 0.33 dB. Moreover, the in-plane anisotropy of Weyl semimetals eliminates one or both polarizers of a conventional isolator geometry, significantly reducing the overall dimensions. These results set the stage for creating highly adaptable, ultra-compact optical isolators that can propel the fields of integrated photonics and quantum technology applications to new heights. Copyright © 2023, The Authors. All rights reserved.

关键词： Energy utilization

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Recent Advancements in Solid State Transformer-based EV Fast Charging Stations

Recent Advancements in Solid State Transformer-based EV Fast...

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International Conference on Power Electronics and Drive systems (PEDS)

作者： Ruvini De Seram Anindita Golder Sheldon S. Williamson Smart Transportation Electrification and Energy Research (STEER) Group Ontario Tech University Oshawa ON Canada Advanced Storage Systems and Electric Transportation (ASSET) Laboratory Ontario Tech University Oshawa ON Canada Ontario Tech-Automotive Center of Excellence (ACE) Ontario Tech University Oshawa ON Canada Department of Electrical and Computer Engineering Faculty of Engineering and Applied Science Ontario Tech University Oshawa ON Canada

Growing deployments of ultra fast charging stations (XFCS) are putting a stress on the existing line-frequency transformer (LFT)-based medium voltage (MV) grid due to the high charging demands of exponentially growing electric vehicles (EV). The conventional LFT occupies a large space in the XFCS installation which introduces challenges in facilitating the XFCS infrastructure. As a result, solid-state transformer (SST)-based XFCS are being developed which can be directly connected to the MV grid and several advantages over LFT-based systems such as compactness, intelligence and availability of the DC link to connect renewable energy sources and storage system can be realized. As such, a detailed analysis of current developments in SST-based XFCS is presented and compared with one another in this paper. The challenges associated with the configurations are examined and direction for future research is identified.

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Leveraging Self-Supervised Learning for MIMO-OFDM Channel Representation and Generation

arXiv

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arXiv 2024年

作者： Liu, Zongxi Chen, Jiacheng Xu, Yunting Ma, Ting Liu, Jingbo Zhou, Haibo Niyato, Dusit The School of Electronic Science and Engineering Nanjing University Nanjing210023 China The Department of Strategic and Advanced Interdisciplinary Research Peng Cheng Laboratory Shenzhen518000 China The School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing210094 China School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Shanghai200240 China The School of Computer Science and Engineering Nanyang Technological University Singapore639798 Singapore

In communications theory, the capacity of multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems is fundamentally determined by wireless channels, which exhibit both diversity and correlation in spatial, frequency and temporal domains. It is further envisioned to exploit the inherent nature of channels, namely representation, to achieve geolocation-based MIMO transmission for 6G, exemplified by the fully-decoupled radio access network (FD-RAN). Accordingly, this paper first employs self-supervised learning to obtain channel representation from unlabeled channel, then proposes a channel generation assisted approach for determining MIMO precoding matrix solely based on geolocation. Specifically, we exploit the small-scale temporal domain variations of channels at a fixed geolocation, and design an ingenious pretext task tailored for contrastive learning. Then, a Transformer-based encoder is trained to output channel representations. We further develop a conditional diffusion generator to generate channel representations from geolocation. Finally, a Transformer-encoder-based decoder is utilized to reconstruct channels from generated representations, where the optimal channel is selected for calculating the precoding matrix for both single and dual BS transmission. We conduct experiments on a public ray-tracing channel dataset, and the extensive simulation results demonstrate the effectiveness of our channel representation method, and also showcase the performance improvement in geolocation-based MIMO transmission. Copyright © 2024, The Authors. All rights reserved.

关键词： MIMO systems

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Higher-Order Topological In-Bulk Corner State in Pure Diffusion systems

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Physical Review Letters 2024年第17期132卷 176302-176302页

作者： Zhoufei Liu Pei-Chao Cao Liujun Xu Guoqiang Xu Ying Li Jiping Huang Department of Physics State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (MOE) Fudan University Shanghai 200438 China State Key Laboratory of Extreme Photonics and Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang University Hangzhou 310027 China International Joint Innovation Center Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang The Electromagnetics Academy of Zhejiang University Zhejiang University Haining 314400 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing 312000 China Graduate School of China Academy of Engineering Physics Beijing 100193 China Department of Electrical and Computer Engineering National University of Singapore Kent Ridge 117583 Republic of Singapore

Compared with conventional topological insulator that carries topological state at its boundaries, the higher-order topological insulator exhibits lower-dimensional gapless boundary states at its corners and hinges. Leveraging the form similarity between Schrödinger equation and diffusion equation, research on higher-order topological insulators has been extended from condensed matter physics to thermal diffusion. Unfortunately, all the corner states of thermal higher-order topological insulator reside within the band gap. Another kind of corner state, which is embedded in the bulk states, has not been realized in pure diffusion systems so far. Here, we construct higher-dimensional Su-Schrieffer-Heeger models based on sphere-rod structure to elucidate these corner states, which we term “in-bulk corner states.” Because of the anti-Hermitian properties of diffusive Hamiltonian, we investigate the thermal behavior of these corner states through theoretical calculation, simulation, and experiment. Furthermore, we study the different thermal behaviors of in-bulk corner state and in-gap corner state. Our results would open a different gate for diffusive topological states and provide a distinct application for efficient heat dissipation.

关键词： Fourier's law Heat transfer Metamaterials

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Mg-Ba Hexa-Spinel Composited Ferrites with Enhanced Magneto-Dielectric Properties for Miniaturized High-Frequency Antennas

SSRN

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SSRN 2024年

作者： Gan, Gongwen Yin, Yaqin Cheng, Yue Luo, Jie Zheng, Zongliang Zhang, Xi Xie, Fei Dian, Liwen Zou, Gaojie Qiu, Feifei Zhu, Zhongyin Gou, Guoqing School of Information Science and Technology Southwest Jiaotong University Chengdu610031 China Microelectronic Research Center Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78758 United States Key Laboratory of Advanced Materials Technology Ministry of Education Southwest Jiaotong University Chengdu610031 China College of Optoelectronic Engineering Xi’an Technological University Xi’an710021 China

We deeply dived multi-phase-based Ba0.16Mg0.84Fe2O4 ferrite for VHF antennas. The structural and magneto-dielectric properties synthesized at various temperatures (1100°C, 1125°C, 1150°C and 1175°C) were investigated. The results demonstrated the coexistence of hexagonal and cubic spinel phases. Microstructure analysis indicated higher temperature induced lager grain size and denser structure. Meanwhile, both the saturation magnetization (from 28 to 25 emu/g) and coercivity (19 to 5 Oe) decreased. In addition, real permeability (μ′) and permittivity (Ε′) arose at higher temperature, promising equivalent permeability and permittivity. What’s more, relatively low magnetic and dielectric losses (tanδμ ~10−2 and tanδΕ ~10-2 to 10−3) promote low energy loss. Finally, a low-profile miniaturized antenna with relative bandwidth of 14.6%, peak gain of 0.98 dB, and radiation efficiency of 74.6% was simulated based on the processed ferrites. In conclusion, the presented investigation greatly improves the magneto-dielectric response, which paves the way to realize high performance in VHF antenna application. © 2024, The Authors. All rights reserved.

关键词： Permittivity

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Computing Safest $st$-Paths in Backbone Networks: Efficiently Solvable Cases and Fast Heuristics

Computing Safest $st$-Paths in Backbone Networks: Efficientl...

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International Workshop on Reliable Networks Design and Modeling (RNDM)

作者： Balázs Vass Péter Revisnyei Alija Pašíć Department of Telecommunications and Artificial Intelligence (TMIT) Faculty of Electrical Engineering and Informatics (VIK) High Speed Networks Laboratory (HSNLab) Budapest University of Technology and Economics (BME) Budapest Hungary Faculty of Mathematics and Computer Science Babeș-Bolyai University Cluj Napoca Romania HUN-REN-BME Information Systems Research Group Budapest Hungary

ISBN: (数字)9798331518189

ISBN: (纸本)9798331518196

For proper evaluation and optimization of the expected availability of a backbone network service, two related very fundamental modeling and algorithmic questions are the following. 1) Realistically estimate the availability of a given $st$ -path for some source and target pair of communicating nodes $s$ and $t$ , and 2) Find a safest $st$ -path. For these, traditional approaches suppose network element failures are independent. In this paper, we show that, by not considering joint failure probabilities, the traditional approaches may misguess the $st$ -path availabilities and, consequently, the total connection availability, which can lead to more frequent Service Level Agreement (SLA) violations and a financial burden on the Communication Service Provider (CSP). Due to the inconsistent estimations, the supposedly safest paths yielded by these approaches may turn out to be suboptimal. On the positive side, we propose a fast algorithmic approach, that, under some assumptions, returns with a (truly) safest $st$ -path accompanied by its exact expected availability. When the aforementioned assumptions do not hold, in our simulations, the proposed algorithmic scheme proved to be a good heuristic, performing at least as well as the traditional method.

关键词： Computational modeling Heuristic algorithms Conferences Estimation Hazards Computational efficiency Optimization Service level agreements

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Merging synthetic and real embryo data for advanced AI predictions

arXiv

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arXiv 2024年

作者： Presacan, Oriana Dorobanţiu, Alexandru Thambawita, Vajira Riegler, Michael A. Stensen, Mette H. Iliceto, Mario Aldea, Alexandru C. Sharma, Akriti Faculty of Electronics Telecommunications and Information Technology National University of Science and Technology Politehnica Bucharest Bucharest061071 Romania Department of Computer Science and Electrical Engineering Lucian Blaga University of Sibiu Sibiu550024 Romania Department of Holistic Systems SimulaMet Stensberggata 27 Oslo0170 Norway Department of Computer Science Oslo Metropolitan University Oslo0167 Norway Volvat Spiren Oslo0176 Norway Faculty of Biotechnologies University of Agronomic Sciences and Veterinary Medicine Bucharest011464 Romania Department of Validation Intelligence for Autonomous Software Systems Simula Research Laboratory Oslo0164 Norway Cyber Security Simula Research Laboratory Oslo0164 Norway

Accurate embryo morphology assessment is essential in assisted reproductive technology for selecting the most viable embryo. Artificial intelligence has the potential to enhance this process. However, the limited availability of embryo data presents challenges for training deep learning models. To address this, we trained two generative models using two datasets—one we created and made publicly available, and one existing public dataset—to generate synthetic embryo images at various cell stages, including 2-cell, 4-cell, 8-cell, morula, and blastocyst. These were combined with real images to train classification models for embryo cell stage prediction. Our results demonstrate that incorporating synthetic images alongside real data improved classification performance, with the model achieving 97% accuracy compared to 94.5% when trained solely on real data. This trend remained consistent when tested on an external Blastocyst dataset from a different clinic. Notably, even when trained exclusively on synthetic data and tested on real data, the model achieved a high accuracy of 92%. Furthermore, combining synthetic data from both generative models yielded better classification results than using data from a single generative model. Four embryologists evaluated the fidelity of the synthetic images through a Turing test, during which they annotated inaccuracies and offered feedback. The analysis showed the diffusion model outperformed the generative adversarial network, deceiving embryologists 66.6% versus 25.3% and achieving lower Fréchet inception distance scores. © 2024, CC BY-SA.

关键词： Generative adversarial networks

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