检索结果-南通市图书馆

Few-shot incremental radar target recognition framework based on scattering-topology properties

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第8期37卷 246-260页

作者： Chenxuan LI Weigang ZHU Bakun ZHU Yonggang LI Graduate School Space Engineering UniversityBeijing 101400China department of electronic and Optical engineering Space Engineering UniversityBeijing 101400China

The continuous emergence of new targets in open scenarios leads to a substantial decrease in the performance of Inverse Synthetic Aperture Radar(ISAR)recognition ***,data scarcity further exacerbates the challenge of identifying new classes of ISAR *** this paper,a few-shot incremental target recognition framework based on Scattering-Topology Properties(STPIL)is ***,STPIL extracts scattering-topology properties of ISAR targets as recognition ***,the pseudo-incremental training strategy effectively alleviates the algorithm’s forgetting of old knowledge,and improves compatibility with new ***,a feature embedding network,with few parameters,is designed based on the graph neural *** embedding network is highly adaptable to changes in data ***,STPIL fully considers the joint distribution and marginal distribution in scattering features,and uses the Brownian distance metric module to make the scattering-topology features more *** results on both the simulation dataset and the public measured data indicate that STPIL can effectively balance new classes with old classes,and has superior performance to other advanced methods in the incremental recognition of targets.

关键词： Brownian distance metric Graph neural networks Incremental learning Inverse Synthetic Aperture Radar(ISAR) Scattering

A Review of State-of-the-art Flexible Power Point Tracking Algorithms in Photovoltaic Systems for Grid Support:Classification and Application

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 1-21页

作者： Mina Haghighat Mehdi Niroomand Hossein Dehghani Tafti Christopher D.Townsend Tyrone Fernando the department of Electrical engineering University of IsfahanIsfahanIran the department of Electrical Electronic and Computer EngineeringUniversity of Western AustraliaCrawley WA 6009Australia

To maximize conversion efficiency,photovoltaic(PV)systems generally operate in the maximum power point tracking(MPPT)***,due to the increasing penetra tion level of PV systems,there is a need for more developed control functions in terms of frequency support services and voltage control to maintain the reliability and stability of the power ***,flexible active power control is a manda tory task for grid-connected PV systems to meet part of the grid ***,a significant number of flexible pow er point tracking(FPPT)algorithms have been introduced in the existing *** purpose of such algorithms is to real ize a cost-effective method to provide grid support functional ities while minimizing the reliance on energy storage *** paper provides a comprehensive overview of grid support functionalities that can be obtained with the FPPT control of PV systems such as frequency support and volt-var *** of these grid support functionalities necessitates PV sys tems to operate under one of the three control strategies,which can be provided with FPPT *** three control strate gies are classified as:①constant power generation control(CP GC),②power reserve control(PRC),and③power ramp rate control(PRRC).A detailed discussion on available FPPT algo rithms for each control strategy is also *** paper can serve as a comprehensive review of the state-of-the-art FPPT algorithms that can equip PV systems with various grid support functionalities.

关键词： Maximum power point tracking(MPPT) flexi ble power point tracking(FPPT) power reserve control(PRC) power ramp rate control(PRRC) low voltage ride-through(LVRT) constant power generation(CPG)

Tunable topological polaritons by dispersion tailoring of an active metasurface

在线全文

学校读者我要写书评

暂无评论

Advanced Photonics 2024年第4期6卷 59-69页

作者： Shaojie Wang Ke Chen Shufang Dong Tian Jiang Junming Zhao Yijun Feng Nanjing University School of Electronic Science and Engineering

Hyperbolic polaritons are known to exist in materials with extreme anisotropy, exhibiting exotic optical properties that enable a plethora of unusual phenomena in the fields of polaritonics and ***, achieving simultaneous low-dimensionality, high-speed controllability, and on-demand reconfigurability of the polaritons remains unexplored despite their excellent potential in light–matter interactions, photonic integrated circuits, and optoelectronic devices. Here, we propose a metasurface approach to integrating artificially engineered electromagnetic anisotropy with fast-controllable electronic elements, offering a new route to realize active topological polaritons. Experiments showcase the proposed reconfigurable metasurface can support real-time transitions of designer polaritons from elliptical to flat, and then to hyperbolic and circular isofrequency contours. Correspondingly, the in-plane surface wavefront undergoes the transitions from convex to collimating, concave, and eventually back to convex. By exploiting the topological variations in polariton dispersions, we observe intriguing phenomena of controllable field canalization and tunable planar focusing. Furthermore, we report the concept of a planar reconfigurable integrated polariton circuit by spatially tailoring the distributions of polariton isofrequency contours, unveiling rich dispersion engineering possibilities and active control capabilities. We may provide an inspiring platform for developing planar active plasmonic devices with potential applications in subdiffraction-resolution imaging,sensing, and information processing.

关键词： active tuning anisotropic polaritons dispersion engineering hyperbolic metasurface topological transitions

Near-field wideband beam training for ELAA with uniform circular array

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第6期67卷 370-383页

作者： Yuhao CHEN Linglong DAI department of electronic engineering Tsinghua UniversityBeijing National Research Center for Information Science and Technology (BNRist)

Extremely large-scale antenna array(ELAA) at millimeter wave(mmWave) and Terahertz(THz)band has been considered a key technology for combating high attenuation in high-frequency bands in future6G communications. Uniform circular arrays(UCAs) have attracted much attention because of their ability to provide flat beamforming gain at all angles. To realize efficient beamforming, beam training is widely used to acquire channel state information. However, with a large antenna number, the beam training overhead in ELAA systems becomes overwhelming. Moreover, with a large bandwidth, the beam defocus effect severely degrades beam training accuracy. To address these issues, this paper proposes a frequency-dependent focusing(FDF)-based beam training scheme to realize effective beam training in near-field wideband ELAA systems with UCA. Specifically, we first analyze the FDF property of UCA, where signals at different subcarriers can simultaneously focus on different distances. Then, by exploiting the FDF property to search different distances using different subcarriers simultaneously, we design a hierarchical codebook and propose an FDFbased beam training scheme. To reveal the effectiveness of the proposed scheme, we compare its necessary beam training overhead with that of existing schemes. Finally, the simulation results demonstrate that the proposed scheme can achieve accurate beam training in near-field wideband UCA systems with a low beam training overhead.

关键词： extremely large-scale antenna array (ELAA) uniform circular array (UCA) near-field wideband beam training

Unknown DDoS Attack Detection with Fuzzy C-Means Clustering and Spatial Location Constraint Prototype Loss

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第2期78卷 2181-2205页

作者： Thanh-Lam Nguyen HaoKao Thanh-Tuan Nguyen Mong-Fong Horng Chin-Shiuh Shieh department of electronic engineering National Kaohsiung University of Science and TechnologyKaohsiung807618Taiwan department of electronic and Automation engineering Nha Trang UniversityNha Trang650000Vietnam

Since its inception,the Internet has been rapidly *** the advancement of science and technology and the explosive growth of the population,the demand for the Internet has been on the *** applications in education,healthcare,entertainment,science,and more are being increasingly deployed based on the ***,malicious threats on the internet are on the rise as *** Denial of Service(DDoS)attacks are among the most common and dangerous threats on the internet *** scale and complexity of DDoS attacks are constantly *** Detection Systems(IDS)have been deployed and have demonstrated their effectiveness in defense against those *** addition,the research of Machine Learning(ML)and Deep Learning(DL)in IDS has gained effective results and significant ***,one of the challenges when applying ML and DL techniques in intrusion detection is the identification of unknown *** attacks,which are not encountered during the system’s training,can lead to misclassification with significant *** this research,we focused on addressing the issue of Unknown Attack Detection,combining two methods:Spatial Location Constraint Prototype Loss(SLCPL)and Fuzzy C-Means(FCM).With the proposed method,we achieved promising results compared to traditional *** proposed method demonstrates a very high accuracy of up to 99.8%with a low false positive rate for known attacks on the Intrusion Detection Evaluation Dataset(CICIDS2017)***,the accuracy is also very high,reaching 99.7%,and the precision goes up to 99.9%for unknown DDoS attacks on the DDoS Evaluation Dataset(CICDDoS2019)*** success of the proposed method is due to the combination of SLCPL,an advanced Open-Set Recognition(OSR)technique,and FCM,a traditional yet highly applicable clustering *** has yielded a novel method in the field of unknown attack *** further expands the trend of applying DL and M

关键词： Cybersecurity DDoS unknown attack detection machine learning deep learning incremental learning convolutional neural networks(CNN) open-set recognition(OSR) spatial location constraint prototype loss fuzzy c-means CICIDS2017 CICDDoS2019

Channel-Feedback-Free Transmission for Downlink FD-RAN:A Radio Map Based Complex-Valued Precoding Network Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2024年第4期21卷 10-22页

作者： Zhao Jiwei Chen Jiacheng Sun Zeyu Shi Yuhang Zhou Haibo Xuemin(Sherman)Shen School of electronic Science and engineering Nanjing UniversityNanjing 210023China College of Information Science and electronic engineering Zhejiang UniversityHangzhou 310058China department of Mathematics and Theories Peng Cheng LaboratoryShenzhen 518000China department of Electrical and Computer engineering University of WaterlooWaterlooOntarioN2L 3G1Canada

As the demand for high-quality services proliferates,an innovative network architecture,the fully-decoupled RAN(FD-RAN),has emerged for more flexible spectrum resource utilization and lower network ***,with the decoupling of uplink base stations and downlink base stations in FDRAN,the traditional transmission mechanism,which relies on real-time channel feedback,is not suitable as the receiver is not able to feedback accurate and timely channel state information to the *** paper proposes a novel transmission scheme without relying on physical layer channel ***,we design a radio map based complex-valued precoding network(RMCPNet)model,which outputs the base station precoding based on user *** comprises multiple subnets,with each subnet responsible for extracting unique modal features from diverse input ***,the multimodal embeddings derived from these distinct subnets are integrated within the information fusion layer,culminating in a unified *** also develop a specific RMCPNet training algorithm that employs the negative spectral efficiency as the loss *** evaluate the performance of the proposed scheme on the public DeepMIMO dataset and show that RMCPNet can achieve 16%and 76%performance improvements over the conventional real-valued neural network and statistical codebook approach,respectively.

关键词： beamforming complex neural networks deep learning FD-RAN

Exciton-polaritons in a 2D hybrid organic-inorganic perovskite microcavity with the presence of optical Stark effect

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第3期33卷 551-555页

作者： Kenneth Coker 郑楚媛 Joseph Roger Arhin Kwame Opuni-Boachie Obour Agyekum 张伟利 School of Information and Communication engineering University of Electronic Science and Technology of ChinaChengdu 611731China department of Electrical and electronic engineering Ho Technical UniversityHo 00233Ghana Telecommunication engineering department Kwame Nkrumah University of Science and TechnologyKumasi 00233Ghana

This study investigates the properties of exciton-polaritons in a two-dimensional(2D)hybrid organic-inorganic perovskite microcavity in the presence of optical Stark *** both steady and dynamic state analyses,strong coupling between excitons of perovskite and cavity photons is revealed,indicating the formation of polaritons in the perovskite ***,it is found that an external optical Stark pulse can induce energy shifts of excitons proportional to the pulse intensity,which modifies the dispersion characteristics of the polaritons.

关键词： exciton-polaritons perovskite microcavity optical Stark effect

Research progress on electronic and active site engineering of cobalt‐based electrocatalysts for oxygen evolution reaction

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第8期6卷 134-165页

作者： Chuansheng He Linlin Yang Jia Wang Tingting Wang Jian Ju Yizhong Lu Wei Chen School of Materials Science and engineering University of JinanJinanChina Catalonia Energy Research Institute—IREC Sant Adriàde BesòsBarcelonaSpain department of electronic and Biomedical engineering University of BarcelonaBarcelonaSpain Graduate School of Integrated Sciences for Life Hiroshima UniversityHigashi‐HiroshimaHiroshimaJapan Wenzhou Institute University of Chinese Academy of SciencesWenzhouChina Oujiang Lab WenzhouChina School of Chemistry and Pharmaceutical Science Guangxi Normal UniversityGuilinChina

Electrocatalytic water splitting has been identified as a potential candidate for producing clean hydrogen energy with zero carbon ***,the sluggish kinetics of oxygen evolution reaction on the anode side of the watersplitting device significantly hinders its practical ***,the efficiency of oxygen evolution processes depends greatly on the availability of cost‐effective catalysts with high activity and *** recent years,extensive theoretical and experimental studies have demonstrated that cobalt(Co)‐based nanomaterials,especially low‐dimensional Co‐based nanomaterials with a huge specific surface area and abundant unsaturated active sites,have emerged as versatile electrocatalysts for oxygen evolution reactions,and thus,great progress has been made in the rational design and synthesis of Co‐based nanomaterials for electrocatalytic oxygen evolution *** the remarkable progress in this area,in this timely review,we highlight the most recent developments in Co‐based nanomaterials relating to their dimensional control,defect regulation(conductivity),electronic structure regulation,and so ***,a brief conclusion about recent progress achieved in oxygen evolution on Co‐based nanomaterials,as well as an outlook on future research challenges,is given.

关键词： Co‐based nanomaterial dimension regulation electronic structure and active site oxygen evolution reaction

Performance Analysis of the Reconfigurable Intelligent Surfaces Communication Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Communications and Information Networks 2024年第2期9卷 184-191页

作者： Omar Abu Ella department of Electrical and electronic engineering Misurata University2659 Zawiat AlmahjoubMisurataLibya

Reconfigurable intelligent surfaces (RIS) play a vital role in meeting the growing demand for higher data rates and reliability in wireless systems. This study focuses on analyzing the performance of RIS systems to gain a deeper understanding of their *** paper presents a mathematical analysis of the RIS system,deriving closed-form formulae that express its characteristics including signal-to-noise ratio(SNR)distribution,ergodic and effective capacity,outage,and error probability. The obtained formulae are newly derived and unconditionally valid solutions. Numerical results demonstrate a close agreement between the derived formulae and MonteCarlo simulation outcomes.

关键词： ergodic capacity effective capacity outage probability bit error rate Rayleigh fading channel RISassisted communication system