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UAV-Assisted Dynamic Avatar Task Migration for Vehicular Metaverse Services: A Multi-Agent Deep Reinforcement Learning Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 430-445页

作者： Jiawen Kang Junlong Chen Minrui Xu Zehui Xiong Yutao Jiao Luchao Han Dusit Niyato Yongju Tong Shengli Xie IEEE School of Automation Guangdong University of TechnologyGuangzhou 510006China 111 Center for Intelligent Batch Manufacturing based on iot Technology Guangzhou 510006China Key Laboratory of Intelligent Information Processing and System Integration of iot Ministry of EducationGuangzhou 510006China School of Computer Science and Engineering Nanyang Technological UniversitySingaporeSingapore Pillar of Information Systems Technology and Design Singapore University of Technology and DesignSingaporeSingapore College of Communication Engineering Army Engineering University of PLANanjing 210007China National Natural Science Foundation of China Beijing 100085China Key Laboratory of Intelligent Detection and iot in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong Key Laboratory of iot Information Technology Guangzhou 510006China

Avatars, as promising digital representations and service assistants of users in Metaverses, can enable drivers and passengers to immerse themselves in 3D virtual services and spaces of UAV-assisted vehicular Metaverses. However, avatar tasks include a multitude of human-to-avatar and avatar-to-avatar interactive applications, e.g., augmented reality navigation,which consumes intensive computing resources. It is inefficient and impractical for vehicles to process avatar tasks locally. Fortunately, migrating avatar tasks to the nearest roadside units(RSU)or unmanned aerial vehicles(UAV) for execution is a promising solution to decrease computation overhead and reduce task processing latency, while the high mobility of vehicles brings challenges for vehicles to independently perform avatar migration decisions depending on current and future vehicle status. To address these challenges, in this paper, we propose a novel avatar task migration system based on multi-agent deep reinforcement learning(MADRL) to execute immersive vehicular avatar tasks dynamically. Specifically, we first formulate the problem of avatar task migration from vehicles to RSUs/UAVs as a partially observable Markov decision process that can be solved by MADRL algorithms. We then design the multi-agent proximal policy optimization(MAPPO) approach as the MADRL algorithm for the avatar task migration problem. To overcome slow convergence resulting from the curse of dimensionality and non-stationary issues caused by shared parameters in MAPPO, we further propose a transformer-based MAPPO approach via sequential decision-making models for the efficient representation of relationships among agents. Finally, to motivate terrestrial or non-terrestrial edge servers(e.g., RSUs or UAVs) to share computation resources and ensure traceability of the sharing records, we apply smart contracts and blockchain technologies to achieve secure sharing management. Numerical results demonstrate that the proposed approach

关键词： Avatar blockchain metaverses multi-agent deep reinforcement learning transformer UAVs

Time and Space Efficient Multi-Model Convolution Vision Transformer for Tomato Disease Detection from Leaf Images with Varied Backgrounds

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Computers, Materials & Continua 2024年第4期79卷 117-142页

作者： Ankita Gangwar Vijaypal Singh Dhaka Geeta Rani Shrey Khandelwal Ester Zumpano Eugenio Vocaturo Department of Computer and Communication Engineering Manipal University JaipurJaipurIndia Department of iot and Intelligent Systems Manipal University JaipurJaipurIndia Department of Computer Engineering ModellingElectronics and Systems(DIMES)University of CalabriaRende(Cosenza)Italy National research Council Institute of Nanotechnology(NANOTEC)Rende(Cosenza)Italy

A consumption of 46.9 million tons of processed tomatoes was reported in 2022 which is merely 20%of the total *** increase of 3.3%in consumption is predicted from 2024 to *** are also rich in iron,potassium,antioxidant lycopene,vitamins A,C and K which are important for preventing cancer,and maintaining blood pressure and glucose ***,tomatoes are globally important due to their widespread usage and nutritional *** face the high demand for tomatoes,it is mandatory to investigate the causes of crop loss and minimize *** are one of the major causes that adversely affect crop yield and degrade the quality of the tomato *** leads to financial losses and affects the livelihood of ***,automatic disease detection at any stage of the tomato plant is a critical *** learning models introduced in the literature show promising results,but the models are difficult to implement on handheld devices such as mobile phones due to high computational costs and a large number of ***,most of the models proposed so far work efficiently for images with plain backgrounds where a clear demarcation exists between the background and leaf ***,the existing techniques lack in recognizing multiple diseases on the same *** address these concerns,we introduce a customized deep learning-based convolution vision transformer *** achieves an accuracy of 93.51%for classifying tomato leaf images with plain as well as complex backgrounds into 13 *** requires a space storage of merely 5.8 MB which is 98.93%,98.33%,and 92.64%less than stateof-the-art visual geometry group,vision transformers,and convolution vision transformermodels,*** training time of 44 min is 51.12%,74.12%,and 57.7%lower than the above-mentioned ***,it can be deployed on(Internet of Things)iot-enabled devices,drones,or mobile devices to assist farmers in the real-time monitoring of tomato *** p

关键词： Tomato disease transformer deep learning mobile devices

Robust textile-based spoof plasmonic frequency scanning antenna for on-body iot applications

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Science China(Information Sciences) 2024年第8期67卷 269-284页

作者： Zhao-Min CHEN Jun-Lin ZHAN Hao CHEN Ya LI Hongjun HE Wu YANG Zhen-Guo LIU Wei-Bing LU State Key Lab of Millimeter Waves School of Information Science and EngineeringSoutheast University Center for Flexible RF Technology Frontiers Science Center for Mobile Information Communication and SecuritySoutheast University Future research Laboratory China Mobile Research Institute Purple Mountain laboratories

Securing a comfortable, wearable compact frequency beam scanning antenna(FBSA) with robustness to deformation, low specific absorption rate(SAR), and good coverage of the surrounding environment for Internet of Things(iot) applications, such as on-body navigation and wireless communication is an emerging challenge. In this work, a robust textile-based spoof plasmonic frequency scanning antenna utilizing higher-order modes is presented, which is also robust to deformation caused by the activities of the human body. The innovative design of the element ensures the high-efficiency transmission of the fundamental mode of spoof surface plasmon polaritons(SSPP) structure, providing the potential of being a multifunctional composite device in the compact on-body network. Besides, an artificial magnetic conductor(AMC) is designed underneath the SSPP structure, obtaining a low SAR value(0.113 W/kg), which ensures the safety of users. As a practical realization of this concept, a textile-based spoof plasmonic antenna was fabricated in the microwave regime and the performed experimental results show the proposed antenna has a single-beam radiation characteristic with a 70° beam scanning angle range when the frequency is 4.7–6.0 GHz with a high average realized gain of 13.15 dBi. And it still maintains a steady performance when faced with structure deformation, which proves its robustness. Wireless communication quality experiments are performed to demonstrate the proposed antenna can measure the angles of targets and realize wireless signal transmission to specific targets as the frequency varies, it may find great potential in the field of on-body iot applications.

关键词： frequency beam scanning antenna (FBSA) Internet of Things (iot) on-body communication spoof surface plasmon polaritons (SSPP) textile-based antenna

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Mitigating set-stuck failure in 3D phase change memory: substituting square pulses with surge pulses

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Science China(Information Sciences) 2024年第5期67卷 295-301页

作者： Ninghua LI Wang CAI Jun XIANG Hao TONG Weiming CHENG Xiangshui MIAO School of Integrated Circuits Huazhong University of Science and Technology Hubei Yangtze Memory laboratories Hubei Institute of Measurement and Testing Technology

In the devices that integrate phase change memory(PCM) and ovonic threshold switching(OTS),the OTS threshold voltage often surpasses the RESET operation voltage of PCM. The conventional application of square pulses hinders the successful completion of the SET operation in these integrated devices. To address this challenge, a novel pulse called the surge pulse is introduced, which comprises a high amplitude pulse for OTS activation and a low amplitude pulse for PCM operation. By employing COMSOL simulation,the operational effectiveness of both square pulses and surge pulses is validated. Test results reveal that using a square pulse to operate the integrated device accelerates the occurrence of SET-stuck failure(SSF).In contrast, the surge pulse enables the integrated device to operate for at least 1000 cycles while preserving the essential cyclic characteristics. Additionally, an investigation into the overshoot component of the surge pulse is conducted, revealing that an increase in overshoot amplitude and pulse width also accelerates the emergence of SSF. By applying the theory of ion migration induced by the electric field, the root cause of SSF in integrated devices is explained, and the accuracy of the theory is validated through the application of a reverse pulse. In summary, this study elucidates the rationality of replacing the square pulse with a surge pulse, presenting a superior approach for operating PCM and OTS integrated devices.

关键词： surge pulse phase change memory (PCM) integration SET-stuck failure (SSF) square pulse

Achieving full mutualism with massive passive devices for multiuser MIMO symbiotic radio

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Science China(Information Sciences) 2024年第9期67卷 196-212页

作者： Jingran XU Zhuoyin DAI Yong ZENG Shi JIN Tao JIANG National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories research Center of 6G Mobile Communications School of Cyber Science and Engineering and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology

Symbiotic radio(SR) is one of the attractive communication technologies to facilitate largescale Internet of Things(iot) connections with enhanced energy and spectrum efficiency, where passive backscatter devices(BDs) modulate their information over the radio frequency(RF) signals emitted by the active primary transmitters(PTs). Meanwhile, the primary transmission can be strengthened with the additional multipaths created by BDs. To capitalize to a greater extent on the mutualism relationship between the two types of communication, this paper studies multiple-input multiple-output(MIMO) SR communication systems including multiple PTs and massive BDs. We derive the achievable rate expressions of each PT and BD, as well as the sum rate expressions of primary and secondary communication, *** asymptotic analysis is given to derive the active and passive communication rates with a large number of BDs. Furthermore, for the general case with a finite number of BDs, we study the precoding optimization problem to maximize the sum rate of primary communication, while ensuring that the sum rate of secondary communication and the individual rate for each PT and BD in the prescribed active and passive user sets satisfy the specified thresholds. Simulation results are presented to verify the analytical studies.

关键词： multiuser MIMO SR backscattering massive backscatter devices asymptotic analysis active and passive communication

Multifunctional SnO_(2) QDs/MXene Heterostructures as Laminar Interlayers for Improved Polysulfide Conversion and Lithium Plating Behavior

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Nano-Micro Letters 2024年第11期16卷 156-169页

作者： Shungui Deng Weiwei Sun Jiawei Tang Mohammad Jafarpour Frank Nüesch Jakob Heier Chuanfang Zhang College of Materials Science and Engineering Sichuan UniversityChengdu 610065People’s Republic of China Laboratory for Functional Polymers Swiss Federal Laboratories for Materials Science and Technology(EMPA)Überlandstrasse 1298600 DübendorfSwitzerland Institute of Materials Science and Engineering Ecole Polytechnique Fédérale de Lausanne(EPFL)Station 121015 LausanneSwitzerland Key Laboratory of Quantum Materials and devices of Ministry of Education School of PhysicsSoutheast UniversityNanjing 211189People’s Republic of China SEU‑FEI Nano‑Pico Center Key Laboratory of MEMS of Ministry of EducationSoutheast UniversityNanjing 210096People’s Republic of China

Poor cycling stability in lithium–sulfur(Li–S)batteries necessitates advanced electrode/electrolyte design and innovative interlayer *** catalysis has emerged as a promising approach,leveraging the adsorption and catalytic performance on lithium polysulfides(LiPSs)to inhibit LiPSs shuttling and improve redox *** this study,we report an ultrathin and laminar SnO_(2)@MXene heterostructure interlayer(SnO_(2)@MX),where SnO_(2) quantum dots(QDs)are uniformly distributed across the MXene *** combined structure of SnO_(2) QDs and MXene,along with the creation of numerous active boundary sites with coordination electron environments,plays a critical role in manipulating the catalytic kinetics of sulfur *** Li–S cell with the SnO_(2)@MX-modified separator not only demonstrates superior electrochemical performance compared to cells with a bare separator but also induces homogeneous Li deposition during *** a result,an areal capacity of 7.6 mAh cm^(-2) under a sulfur loading of 7.5 mg cm^(-2) and a high stability over 500 cycles are *** work demonstrates a feasible strategy of utilizing a laminar separator interlayer for advanced Li–S batteries awaiting commercialization and may shed light on the understanding of heterostructure catalysis with enhanced reaction kinetics.

关键词： Lithium-sulfur battery Heterogeneous catalysis Heterostructure Redox kinetics Lithium dendrites

用于损耗型集成光子器件的相变材料评价标准和设计策略

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Science China Materials 2024年第6期67卷 2008-2015页

作者：夏剑董云潇龚俊桀王子炫王天赐杨蕊缪向水 School of Integrated Circuits Huazhong University of Science and TechnologyWuhan 430074China Hubei Yangtze Memory laboratories Wuhan 430205China

相变材料(PCM)具有优异的光学性质,在多种集成光子器件中极具应用前景,如光存储器、光开关和光神经形态计算器件.然而,由于集成光子器件相变材料光学性能评价标准的缺乏,新型相变材料的设计主要依赖于研究者的研究经验.本文基于相变光... 详细信息

相变材料(PCM)具有优异的光学性质,在多种集成光子器件中极具应用前景,如光存储器、光开关和光神经形态计算器件.然而,由于集成光子器件相变材料光学性能评价标准的缺乏,新型相变材料的设计主要依赖于研究者的研究经验.本文基于相变光子器件的性能需求,引入材料品质因子(FOM2=Δk/kamor)来评价相变材料的光学性能,建立了针对损耗调制型相变光子器件相变材料的光学性能评价标准.FOM值的大小代表相变材料在构建高性能相变光子器件中的应用潜力,FOM值越大,相变材料应用于光子器件的限制就越小.在此基础上,本文基于光学带隙理论,建立了相变材料光学参数与FOM值之间的关系,开发了三种基于GST的新型光学相变材料.结果表明,氮等非金属元素掺杂可以提高GST的FOM值,有利于开发低损耗、高调制空间的损耗型相变光子器件和大规模损耗型相变光子阵列.除了FOM之外,相变材料的结晶温度也会影响器件的编程功耗、循环寿命和稳定性,这要求我们在实际应用场景中根据器件的需求选择合适的相变材料.总之,本文为相变材料的光学性能提供了评价标准,促进了集成光子器件应用中相变材料的定制设计.

关键词： phase change materials figure of merit optical bandgap photonic devices

Two-dimensional materials for future information technology: status and prospects

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Science China(Information Sciences) 2024年第6期67卷 1-147页

作者： Hao QIU Zhihao YU Tiange ZHAO Qi ZHANG Mingsheng XU Peifeng LI Taotao LI Wenzhong BAO Yang CHAI Shula CHEN Yiqi CHEN Hui-Ming CHENG Daoxin DAI Zengfeng DI Zhuo DONG Xidong DUAN Yuhan FENG Yu FU Jingshu GUO Pengwen GUO Yue HAO Jun HE Xiao HE Jingyi HU Weida HU Zehua HU Xinyue HUANG Ziyang HUANG Ali IMRAN Ziqiang KONG Jia LI Qian LI Weisheng LI Lei LIAO Bilu LIU Can LIU Chunsen LIU Guanyu LIU Kaihui LIU Liwei LIU Sheng LIU Yuan LIU Donglin LU Likuan MA Feng MIAO Zhenhua NI Jing NING Anlian PAN Tian-Ling REN Haowen SHU Litao SUN Yue SUN Quanyang TAO Zi-Ao TIAN Dong WANG Hao WANG Haomin WANG Jialong WANG Junyong WANG Wenhui WANG Xingjun WANG Yeliang WANG Yuwei WANG Zhenyu WANG Yao WE... School of Electronic Science and Engineering Nanjing University School of Integrated Circuits Interdisciplinary Research Center for Future Intelligent Chips (Chip-X)Nanjing University School of Integrated Circuit Science and Engineering Nanjing University of Posts and Telecommunications State Key Laboratory of Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences School of Physics and Key Lab of Quantum Materials and devices of the Ministry of Education School of Electronic Science & EngineeringSoutheast University College of Integrated Circuits State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University Suzhou Laboratory State Key Laboratory of Integrated Chips and Systems School of MicroelectronicsFudan University Shaoxin Laboratory Department of Applied Physics The Hong Kong Polytechnic University Key Laboratory for Micro-Nano Physics and Technology of Hunan Province College of Materials Science and EngineeringHunan University College of Integrated Circuits Zhejiang University Shenzhen Geim Graphene Center Shenzhen Key Laboratory of Layered Materials for Value-Added ApplicationsTsinghua-Berkeley Shenzhen Institute & Institute of Materials ResearchTsinghua Shenzhen International Graduate SchoolTsinghua University State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and EngineeringInternational Research Center for Advanced PhotonicsZijingang CampusZhejiang University National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences CAS Key Laboratory of Nanophotonic Materials and devices & Key Laboratory of Nanodevices and Applications i-LabSuzhou Institute of Nano-Tech and Nano-Bionics (SINANO)Chinese Academy of Sciences College of Chemistry and Chemical Engineering Hunan University Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education) Department of PhysicsRenmin University of China School

Over the past 70 years, the semiconductor industry has undergone transformative changes,largely driven by the miniaturization of devices and the integration of innovative structures and materials. Two-dimensional(2D) materials like transition metal dichalcogenides(TMDs) and graphene are pivotal in overcoming the limitations of silicon-based technologies, offering innovative approaches in transistor design and functionality, enabling atomic-thin channel transistors and monolithic 3D integration. We review the important progress in the application of 2D materials in future information technology, focusing in particular on microelectronics and optoelectronics. We comprehensively summarize the key advancements across material production, characterization metrology, electronic devices, optoelectronic devices, and heterogeneous integration on silicon. A strategic roadmap and key challenges for the transition of 2D materials from basic research to industrial development are outlined. To facilitate such a transition, key technologies and tools dedicated to 2D materials must be developed to meet industrial standards, and the employment of AI in material growth, characterizations, and circuit design will be essential. It is time for academia to actively engage with industry to drive the next 10 years of 2D material research.

关键词： two-dimensional (2D) materials information technology production technology standardization of characterization microelectronicdevices optoelectronic devices multi-functional integration

Chiral phonon activated spin Seebeck effect in chiral materials

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 149-155页

作者： Xiao Li Jinxin Zhong Jinluo Cheng Hao Chen Huiqian Wang Jun Liu Dali Sun Lifa Zhang Jun Zhou Phonon Engineering research Center of Jiangsu Province Center for Quantum Transport and Thermal Energy ScienceSchool of Physics and TechnologyNanjing Normal UniversityNanjing 210023China Center for Phononics and Thermal Energy Science China-EU Joint Lab for NanophononicsSchool of Physics Science and EngineeringTongji UniversityShanghai 200092China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of ScienceChangchun 130033China Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleigh NC 27606USA Department of Physics North Carolina State UniversityRaleigh NC 27695USA Organic and Carbon Electronics laboratories(ORaCEL) North Carolina State UniversityRaleigh NC 27606USA

Efficient generation of spin polarization is very important for spintronics and quantum computation. In chiral materials without magnetic order nor spin-orbit coupling, we find a new spin selectivity effect—chiral phonon activated spin Seebeck(CPASS)effect. Starting with the nonequilibrium distribution of chiral phonons under a temperature gradient, the CPASS coefficients are computed based on the Boltzmann transport theory. With both the phonon-drag and band transport contributions, the spin accumulations generated by the CPASS effect exhibit quadratic dependence on the temperature gradient. The strength of the CPASS effect and the relative magnitude of both contributions are tunable by the chemical potential modulation. The CPASS effect, which gives a promising explanation on the traditional chiral-induced spin selectivity effect, provides opportunities for the exploration of advanced spintronic devices based on chiral materials even in the absence of any magnetic order and spin-orbit coupling.

关键词： spin Seebeck effect chiral phonon phonon-drag contribution efficient spin generation