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Reconfigurable intelligent surfaces for wireless communications:Overview of hardware designs,channel models,and estimation techniques

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Intelligent and Converged Networks 2022年第1期3卷 1-32页

作者： Mengnan Jian George C.Alexandropoulos Ertugrul Basar Chongwen Huang Ruiqi Liu Yuanwei Liu Chau Yuen the Wireless Research Institute ZTE CorporationBeijing 100029China the State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen 518055China Department of Informatics and Telecommunications National and Kapodistrian University of AthensAthens 15784Greece Communications Research and Innovation Laboratory(CoreLab) Department of Electrical and Electronics EngineeringKoçUniversityIstanbul 34450Turkey College of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027China School of Electronic Engineering and Computer Science Queen Mary University of LondonLondonE14NSUK. the Engineering Product Development(EPD)Pillar Singapore University of Technology and DesignSingapore 487372Singapore

The demanding objectives for the future sixth generation(6G)of wireless communication networks have spurred recent research efforts on novel materials and radio-frequency front-end architectures for wireless connectivity,as well as revolutionary communication and computing *** the pioneering candidate technologies for 6G belong the reconfigurable intelligent surfaces(RISs),which are artificial planar structures with integrated electronic circuits that can be programmed to manipulate the incoming electromagnetic field in a wide variety of *** RISs in wireless networks have been recently advocated as a revolutionary means to transform any wireless signal propagation environment to a dynamically programmable one,intended for various networking objectives,such as coverage extension and capacity boosting,spatiotemporal focusing with benefits in energy efficiency and secrecy,and low electromagnetic field *** by the recent increasing interests in the field of RISs and the consequent pioneering concept of the RIS-enabled smart wireless environments,in this paper,we overview and taxonomize the latest advances in RIS hardware architectures as well as the most recent developments in the modeling of RIS unit elements and RIS-empowered wireless signal *** also present a thorough overview of the channel estimation approaches for RIS-empowered communications systems,which constitute a prerequisite step for the optimized incorporation of RISs in future wireless ***,we discuss the relevance of the RIS technology in the latest wireless communication standards,and highlight the current and future standardization activities for the RIS technology and the consequent RIS-empowered wireless networking approaches.

关键词： reconfigurable intelligent surfaces beyond 5G 6G channel modeling hardware architecture channel estimation smart wireless environment standardization

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Employing the Vernier Effect for Sensitivity Enhancement in a Distributed Optical Fiber Sensor

Employing the Vernier Effect for Sensitivity Enhancement in ...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Chen Zhu Jie Huang Research Center for Optical Fiber Sensing Zhejiang Laboratory Hangzhou China Department of Electrical and Computer Engineering Missouri University of Science and Technology Rolla MO USA

Distributed optical fiber sensing based on microwave photonics with significantly improved and tunable sensitivity enabled by the distributed Vernier effect is demonstrated.

ISBN: (纸本)9781957171258

Distributed optical fiber sensing based on microwave photonics with significantly improved and tunable sensitivity enabled by the distributed Vernier effect is demonstrated.

关键词： Microwave photonics Multimode interference Optical fibers Optical frequency domain reflectometry Optical sensing Optical signals

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Fabry-Perot Interferometer in a Coreless Fiber Fabricated by a Fs Laser for High-Temperature Applications

Fabry-Perot Interferometer in a Coreless Fiber Fabricated by...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Chen Zhu Jie Huang Zhejiang Laboratory Research Center for Optical Fiber Sensing Hangzhou China Department of Electrical and Computer Engineering Missouri University of Science and Technology Rolla MO USA

An optical fiber in-line Fabry-Perot interferometer (FPI) fabricated in a no-core fiber using the direct femtosecond laser writing technique for high-temperature sensing applications is reported.

ISBN: (纸本)9781957171258

An optical fiber in-line Fabry-Perot interferometer (FPI) fabricated in a no-core fiber using the direct femtosecond laser writing technique for high-temperature sensing applications is reported.

关键词： Fabry Perot interferometers Femtosecond fiber lasers Femtosecond laser writing Optical fibers Silica fibers Single crystal fibers

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An Enhanced Resource Selection Scheme for Efficient Intra-Platoon Message Delivery

An Enhanced Resource Selection Scheme for Efficient Intra-Pl...

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2024 IEEE Global Communications Conference, GLOBECOM 2024

作者： Wang, Bingying Zheng, Jun Li, Cheng Nanjing University of Information Science and Technology School of Electronics and Information Engineering Nanjing210044 China Southeast University National Mobile Communications Research Laboratory Frontiers Science Center for Mobile Information Communication and Security Nanjing210096 China Purple Mountain Laboratories Nanjing211111 China Simon Fraser University School of Engineering Science BurnabyBCV5A 1S6 Canada Memorial University Department of Electrical and Computer Engineering St. John'sNLA1B 3X5 Canada

ISBN: (纸本)9798350351255

This paper proposes an enhanced resource selection (eInP-RS) scheme for efficient intra-platoon message delivery of cooperative awareness messages (CAMs) and decentralized environmental notification messages (DENMs). To achieve this goal, the eInP-RS scheme allows each vehicle to transmit CAM and DENM packets on a C-V2X channel (CH1) and an 802.11p channel (CH2), separately, and introduces four mechanisms to enhance the standardized sensing-based SPS scheme. A contention window (CW) size adjustment mechanism is introduced to enable a vehicle to adjust its CW size according to the information it collects on CH1 in order to avoid potential packet collisions on CH2;a resource partition mechanism is introduced to divide frequency-time resources in a selection window into two sets in order for vehicles moving in opposite directions to select different resources and thus avoid potential merging collisions on CH1;an intra-platoon cooperation mechanism is introduced to enable the PL of a platoon to know the resource and channel occupation information of the platoon's hidden nodes on CH1 and CH2;and a packet collision detection mechanism is used to enable a non-platoon vehicle to detect packet collisions occurring on both channels after a lane-changing maneuver to avoid potential merging collisions. Simulation results show that the proposed eInP-RS scheme outperforms the standardized sensing-based SPS scheme in terms of the intra-platoon CAM/DENM delivery ratio and the average intra-platoon DENM delivery delay. © 2024 IEEE.

关键词： Magnetic levitation vehicles

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SecBCS: a secure and privacy-preserving blockchain-based crowdsourcing system

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science China(Information sciences) 2020年第3期63卷 20-33页

作者： Chao LIN Debiao HE Sherali ZEADALLY Neeraj KUMAR Kim-Kwang Raymond CHOO Key Laboratory of Aerospace Information Security and Trusted Computing Ministry of EducationSchool of Cyber Science and Engineering Wuhan University State Key Laboratory of Cryptology College of Communication and Information University of Kentucky Department of Computer Science and Engineering Thapar University Department of Information Systems and Cyber Security and Department of Electrical and Computer Engineering University of Texas at San Antonio

A robust and scalable crowd management infrastructure is crucial in addressing operational challenges when deploying high-density sensors and actuators in a smart city. While crowdsourcing is widely used in crowd management, conventional solutions, such as Upwork and Amazon Mechanical Turk, generally depend on a trusted third-party platform. There exist several potential security concerns(e.g., sensitive leakage, single point of failure and unfair judgment) in such a centralized paradigm. Hence, a recent trend in crowdsourcing is to leverage blockchain(a decentralized ledger technology) to address some of the existing limitations. A small number of blockchain-based crowdsourcing systems(BCSs) with incentive mechanisms have been proposed in the literature, but they are generally not designed with security in mind. Thus, we study the security and privacy requirements of a secure BCS and propose a concrete solution(i.e., SecBCS)with a prototype implementation based on JUICE.

关键词： crowdsourcing blockchain secure privacy-preserving smart contract

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DiffDVC: Accurate Event Detection for Dense Video Captioning via Diffusion Models 39

DiffDVC: Accurate Event Detection for Dense Video Captioning...

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39th Annual AAAI Conference on Artificial Intelligence, AAAI 2025

作者： Chen, Wei Niu, Jianwei Liu, Xuefeng Wang, Zhendong Tang, Shaojie Zhu, Guogang State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing China Zhongguancun Laboratory Beijing China Zhengzhou University Research Institute of Industrial Technology Zhengzhou University Zhengzhou China Department of Management Science and Systems University at Buffalo BuffaloNY United States

ISBN: (纸本)157735897X

Dense video captioning (DVC) aims to describe multiple events within a video, and its performance is greatly affected by the accuracy of video event detection. Video event detection involves predicting the proposal boundaries (start and end times) and the classification score of each event in a video. Recently, a few methods have applied diffusion models originally designed for image object detection to detect events in DVC. These methods add noise to the ground-truth event proposal boundaries, and subsequently learn the denoising process. However, these methods often overlook the fundamental differences between videos and images. We observe that, whereas in images the important information for object classification is normally around the boundaries of the ground-truth boxes, in videos the key information for event classification is typically centered in the middle of ground-truth event proposals. As a result, the classification module in these existing diffusion models becomes insensitive to boundary changes introduced by the added noise, leading to suboptimal performance. This paper introduces DiffDVC, an innovative diffusion model for DVC. The core of DiffDVC is a boundary-sensitive detector. The detector increases the sensitivity of the classification module to boundary changes by focusing on frames within a specific range around the start and end times of noisy event proposals. Additionally, this range is dynamically adjusted to suit different event proposals. Comprehensive experiments on ActivityNet-1.3, ActivityNet Captions, and YouCook2 datasets show DiffDVC achieving superior performance. Copyright © 2025, Association for the Advancement of Artificial Intelligence (***). All rights reserved.

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Zero-Change CMOS Nanophotonics: Converting Foundry Semiconductor Chips to Plasmonic Electro-optic Modulators

Zero-Change CMOS Nanophotonics: Converting Foundry Semicondu...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Mohamed ElKabbash Isaac Harris Sivan Trajtenberg-Mills Saumil Bandyopadhyay Xibi Chen Mohamed I. Ibrahim Ruonan Han Dirk Englund Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA USA Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA

We create nanophotonic devices using CMOS foundry processes where the top metal layers exhibit a plasmonic resonance. By integrating liquid crystals and applying a bias, we measure a 20 nm resonance shift at ~700 nm.

ISBN: (纸本)9781957171258

关键词： Electrooptical modulators Liquid crystals Nanophotonics Red shift Refractive index Resonance

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An Unstructured Body-of-Revolution Electromagnetic Particle-in-Cell Algorithm with Radial Perfectly Matched Layers and Dual Polarizations

arXiv

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arXiv 2024年

作者： Na, Dong-Yeop Teixeira, Fernando L. Omelchenko, Yuri A. Department of Electrical Engineering Pohang University of Science and Technology Pohang37673 Korea Republic of ElectroScience Laboratory Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43212 United States Trinum Research Inc. San DiegoCA92126 United States

A novel electromagnetic particle-in-cell algorithm has been developed for fully kinetic plasma simulations on unstructured (irregular) meshes in complex body-of-revolution geometries. The algorithm, implemented in the BORPIC++ code, utilizes a set of field scalings and a coordinate mapping, reducing the Maxwell field problem in a cylindrical system to a Cartesian finite element Maxwell solver in the meridian plane. The latter obviates the cylindrical coordinate singularity in the symmetry axis. The choice of an unstructured finite element discretization enhances the geometrical flexibility of the BORPIC++ solver compared to the more traditional finite difference solvers. Symmetries in Maxwell's equations are explored to decompose the problem into two dual polarization states with isomorphic representations that enable code reuse. The particle-in-cell scatter and gather steps preserve charge-conservation at the discrete level. Our previous algorithm (BORPIC+) discretized the E and B field components of TEφ and TMφ polarizations on the finite element (primal) mesh [1, 2]. Here, we employ a new field-update scheme. Using the same finite element (primal) mesh, this scheme advances two sets of field components independently: (1) E and B of TEφ polarized fields, (Ez,Eρ,Bφ) and (2) D and H of TMφ polarized fields, (Dφ,Hz,Hρ). Since these field updates are not explicitly coupled, the new field solver obviates the coordinate singularity, which otherwise arises at the cylindrical symmetric axis, ρ = 0 when defining the discrete Hodge matrices (generalized finite element mass matrices). A cylindrical perfectly matched layer is implemented as a boundary condition in the radial direction to simulate open space problems, with periodic boundary conditions in the axial direction. We investigate effects of charged particles moving next to the cylindrical perfectly matched layer. We model azimuthal currents arising from rotational motion of charged rings, which produce TMφ polarized

关键词： Maxwell equations

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Train Faster, Perform Better: Modular Adaptive Training in Over-Parameterized Models

arXiv

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arXiv 2024年

作者： Shi, Yubin Chen, Yixuan Dong, Mingzhi Yang, Xiaochen Li, Dongsheng Wang, Yujiang Dick, Robert Lv, Qin Zhao, Yingying Yang, Fan Lu, Tun Gu, Ning Shang, Li China and Shanghai Key Laboratory of Data Science School of Computer Science Fudan University China School of Mathematics Statistics University of Glasgow United Kingdom Microsoft Research Asia Shanghai China Department of Engineering Science University of Oxford United Kingdom Department of Electrical Engineering and Computer Science University of Michigan United States Department of Computer Science University of Colorado Boulder United States School of Microelectronics Fudan University China

Despite their prevalence in deep-learning communities, over-parameterized models convey high demands of computational costs for proper training. This work studies the fine-grained, modular-level learning dynamics of over-parameterized models to attain a more efficient and fruitful training strategy. Empirical evidence reveals that when scaling down into network modules, such as heads in self-attention models, we can observe varying learning patterns implicitly associated with each module's trainability. To describe such modular-level learning capabilities, we introduce a novel concept dubbed modular neural tangent kernel (mNTK), and we demonstrate that the quality of a module's learning is tightly associated with its mNTK's principal eigenvalue λmax. A large λmax indicates that the module learns features with better convergence, while those miniature ones may impact generalization negatively. Inspired by the discovery, we propose a novel training strategy termed Modular Adaptive Training (MAT) to update those modules with their λmax exceeding a dynamic threshold selectively, concentrating the model on learning common features and ignoring those superfluous ones. Unlike most existing training schemes with a complete BP cycle across all network modules, MAT can significantly save computations by its partially-updating strategy and can further improve performance. Experiments show that MAT nearly halves the computational cost of model training and outperforms the accuracy of baselines. © 2024, CC BY.

关键词： Eigenvalues and eigenfunctions

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Advances in lithium niobate photonics:development status and perspectives

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Advanced Photonics 2022年第3期4卷 40-82页

作者： Guanyu Chen Nanxi Li Jun Da Ng Hong-Lin Lin Yanyan Zhou Yuan Hsing Fu Lennon Yao Ting Lee Yu Yu Ai-Qun Liu Aaron J.Danner National University of Singapore Department of Electrical and Computer EngineeringSingapore A*STAR(Agency for Science Technology and Research)Institute of MicroelectronicsSingapore Huazhong University of Science and Technology School of Optical and Electronic InformationWuhan National Laboratory for OptoelectronicsWuhanChina Nanyang Technological University Quantum Science and Engineering CentreSingapore

Lithium niobate(LN)has experienced significant developments during past decades due to its versatile properties,especially its large electro-optic(EO)*** example,bulk LN-based modulators with high speeds and a superior linearity are widely used in typical fiber-optic communication ***,with everincreasing demands for signal transmission capacity,the high power and large size of bulk LN-based devices pose great challenges,especially when one of its counterparts,integrated silicon photonics,has experienced dramatic developments in recent *** long ago,high-quality thin-film LN on insulator(LNOI)became commercially available,which has paved the way for integrated LN photonics and opened a hot research area of LN photonics *** allows a large refractive index contrast,thus light can be confined within a more compact *** with other properties of LN,such as nonlinear/acousto-optic/pyroelectric effects,various kinds of high-performance integrated LN devices can be demonstrated.A comprehensive summary of advances in LN photonics is *** LN photonics has experienced several decades of development,our review includes some of the typical bulk LN devices as well as recently developed thin film LN *** this way,readers may be inspired by a complete picture of the evolution of this *** first introduce the basic material properties of LN and several key processing technologies for fabricating photonics *** that,various kinds of functional devices based on different effects are ***,we give a short summary and perspective of LN *** hope this review can give readers more insight into recent advances in LN photonics and contribute to the further development of LN related research.

关键词： lithium niobate etching photonics integrated optics nanotechnology devices.

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