期刊文献+
共找到2,869篇文章
< 1 2 144 >
每页显示 20 50 100
Structural engineering of potassium vanadate cathode by pre-intercalated Mg_(2+) for high-performance and durable rechargeable aqueous zinc-ion batteries
1
作者 Ashok Kumar Kakarla Hari Bandi +2 位作者 Wasim Akram Syed R.Shanthappa Jae Su Yu 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第9期3780-3793,共14页
Aqueous zinc(Zn)-ion batteries(AZIBs)have the potential to be used in massive energy storage owing to their low cost,eco-friendliness,safety,and good energy density.Significant research has been focused on enhancing t... Aqueous zinc(Zn)-ion batteries(AZIBs)have the potential to be used in massive energy storage owing to their low cost,eco-friendliness,safety,and good energy density.Significant research has been focused on enhancing the performance of AZIBs,but challenges persist.Vanadium-based oxides,known for their large interlayer spacing,are promising cathode materials.In this report,we synthesize Mg^(2+)-intercalated potassium vanadate(KVO)(MgKVO)via a single-step hydrothermal method and achieve a 12.2°Ainterlayer spacing.Mg^(2+) intercalation enhances the KVO performance,providing wide channels for Zn^(2+),which results in high capacity and ion diffusion.The combined action of K^(+) and Mg^(2+) intercalation enhances the electrical conductivity of MgKVO.This structural design endows MgKVO with excellent electrochemical performance.The AZIB with the MgKVO cathode delivers a high capacity of 457 mAh g^(-1) at 0.5 A g^(-1),excellent rate performance of 298 mAh g^(-1) at 5 A g^(-1),and outstanding cycling stability of 102%over 1300 cycles at 3 A g^(-1).Additionally,pseudocapacitance analysis reveals the high capacitance contribution and Zn^(2+)diffusion coefficient of MgKVO.Notably,ex-situ X-ray diffraction,X-ray photoelectron spectroscopy,and Raman analyses further demonstrate the Zn^(2+)insertion/extraction and Zn-ion storage mechanisms that occurred during cycling in the battery system.This study provides new insights into the intercalation of dual cations in vanadium oxides and offers new solutions for designing cathodes for high-capacity AZIBs. 展开更多
关键词 Metal-ion intercalation Hydrothermal Rate capability CATHODE Aqueous zinc-ion batteries
下载PDF
Wireless Information and Power Transfer in Underwater Acoustic Sensor Networks
2
作者 Feng Yizhi Ji Fei 《China Communications》 SCIE CSCD 2024年第10期256-266,共11页
Wireless information and power transfer(WIPT) enables simultaneously communications and sustainable power supplement without the erection of power supply lines and the replacement operation of the batteries for the te... Wireless information and power transfer(WIPT) enables simultaneously communications and sustainable power supplement without the erection of power supply lines and the replacement operation of the batteries for the terminals. The application of WIPT to the underwater acoustic sensor networks(UWASNs) not only retains the long range communication capabilities, but also provides an auxiliary and convenient energy supplement way for the terminal sensors, and thus is a promising scheme to solve the energy-limited problem for the UWASNs. In this paper, we propose the integration of WIPT into the UWASNs and provide an overview on various enabling techniques for the WIPT based UWASNs(WIPT-UWASNs) as well as pointing out future research challenges and opportunities for WIPT-UWASNs. 展开更多
关键词 underwater acoustic modem underwater acoustic sensor network(UWASN) wireless information and power transfer(WIPT)
下载PDF
Flight parameter calculation method of multi-projectiles using temporal and spatial information constraint 被引量:1
3
作者 Han-shan Li Xiao-qian Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第1期63-75,共13页
The dynamic parameters of multiple projectiles that are fired using multi-barrel weapons in highfrequency continuous firing modes are important indicators to measure the performance of these weapons.The characteristic... The dynamic parameters of multiple projectiles that are fired using multi-barrel weapons in highfrequency continuous firing modes are important indicators to measure the performance of these weapons.The characteristics of multiple projectiles are high randomness and large numbers launched in a short period of time,making it very difficult to obtain the real dispersion parameters of the projectiles due to the occlusion or coincidence of multiple projectiles.Using six intersecting-screen testing system,in this paper,we propose an association recognition and matching algorithm of multiple projectiles using a temporal and spatial information constraint mechanism.We extract the output signal from each detection screen and then use the wavelet transform to process the output signal.We present a method to identify and extract the time values on which the projectiles pass through the detection screens using the wavelet transform modulus maximum theory.We then use the correlation of the output signals of three parallel detection screens to establish a correlation coefficient recognition constraint function for the multiple projectiles.Based on the premise of linear projectile motion,we establish a temporal and spatial constraint matching model using the projectile’s position coordinates in each detection screen and the projectile’s time constraints within the multiple intersecting-screen geometry.We then determine the time values of the multiple projectiles in each detection screen using an iterative search cycle registration,and finally obtain the flight parameters for the multiple projectiles in the presence of uncertainty.The proposed method and algorithm were verified experimentally and can solve the problem of uncertainty in projectiles flight parameter under different multiple projectile firing states. 展开更多
关键词 Six detection screen array Multi-projectile Recognition and matching Temporal and spatial information constraint Wavelet transform
下载PDF
Evolutionary Decision-Making and Planning for Autonomous Driving Based on Safe and Rational Exploration and Exploitation 被引量:2
4
作者 Kang Yuan Yanjun Huang +4 位作者 Shuo Yang Zewei Zhou Yulei Wang Dongpu Cao Hong Chen 《Engineering》 SCIE EI CAS CSCD 2024年第2期108-120,共13页
Decision-making and motion planning are extremely important in autonomous driving to ensure safe driving in a real-world environment.This study proposes an online evolutionary decision-making and motion planning frame... Decision-making and motion planning are extremely important in autonomous driving to ensure safe driving in a real-world environment.This study proposes an online evolutionary decision-making and motion planning framework for autonomous driving based on a hybrid data-and model-driven method.First,a data-driven decision-making module based on deep reinforcement learning(DRL)is developed to pursue a rational driving performance as much as possible.Then,model predictive control(MPC)is employed to execute both longitudinal and lateral motion planning tasks.Multiple constraints are defined according to the vehicle’s physical limit to meet the driving task requirements.Finally,two principles of safety and rationality for the self-evolution of autonomous driving are proposed.A motion envelope is established and embedded into a rational exploration and exploitation scheme,which filters out unreasonable experiences by masking unsafe actions so as to collect high-quality training data for the DRL agent.Experiments with a high-fidelity vehicle model and MATLAB/Simulink co-simulation environment are conducted,and the results show that the proposed online-evolution framework is able to generate safer,more rational,and more efficient driving action in a real-world environment. 展开更多
关键词 Autonomous driving DECISION-MAKING Motion planning Deep reinforcement learning Model predictive control
下载PDF
The Roadmap of 2D Materials and Devices Toward Chips 被引量:4
5
作者 Anhan Liu Xiaowei Zhang +16 位作者 Ziyu Liu Yuning Li Xueyang Peng Xin Li Yue Qin Chen Hu Yanqing Qiu Han Jiang Yang Wang Yifan Li Jun Tang Jun Liu Hao Guo Tao Deng Songang Peng He Tian Tian‑Ling Ren 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第6期343-438,共96页
Due to the constraints imposed by physical effects and performance degra certain limitations in sustaining the advancement of Moore’s law.Two-dimensional(2D)materials have emerged as highly promising candidates for t... Due to the constraints imposed by physical effects and performance degra certain limitations in sustaining the advancement of Moore’s law.Two-dimensional(2D)materials have emerged as highly promising candidates for the post-Moore era,offering significant potential in domains such as integrated circuits and next-generation computing.Here,in this review,the progress of 2D semiconductors in process engineering and various electronic applications are summarized.A careful introduction of material synthesis,transistor engineering focused on device configuration,dielectric engineering,contact engineering,and material integration are given first.Then 2D transistors for certain electronic applications including digital and analog circuits,heterogeneous integration chips,and sensing circuits are discussed.Moreover,several promising applications(artificial intelligence chips and quantum chips)based on specific mechanism devices are introduced.Finally,the challenges for 2D materials encountered in achieving circuit-level or system-level applications are analyzed,and potential development pathways or roadmaps are further speculated and outlooked. 展开更多
关键词 Two-dimensional materials ROADMAP Integrated circuits Post-Moore era
下载PDF
Targeted regeneration and upcycling of spent graphite by defect‐driven tin nucleation 被引量:1
6
作者 Zhiheng Cheng Zhiling Luo +7 位作者 Hao Zhang Wuxing Zhang Wang Gao Yang Zhang Long Qie Yonggang Yao Yunhui Huang Kun Kelvin Fu 《Carbon Energy》 SCIE EI CAS CSCD 2024年第4期91-103,共13页
The recycling of spent batteries has become increasingly important owing to their wide applications,abundant raw material supply,and sustainable development.Compared with the degraded cathode,spent anode graphite ofte... The recycling of spent batteries has become increasingly important owing to their wide applications,abundant raw material supply,and sustainable development.Compared with the degraded cathode,spent anode graphite often has a relatively intact structure with few defects after long cycling.Yet,most spent graphite is simply burned or discarded due to its limited value and inferior performance on using conventional recycling methods that are complex,have low efficiency,and fail in performance restoration.Herein,we propose a fast,efficient,and“intelligent”strategy to regenerate and upcycle spent graphite based on defect‐driven targeted remediation.Using Sn as a nanoscale healant,we used rapid heating(~50 ms)to enable dynamic Sn droplets to automatically nucleate around the surface defects on the graphite upon cooling owing to strong binding to the defects(~5.84 eV/atom),thus simultaneously achieving Sn dispersion and graphite remediation.As a result,the regenerated graphite showed enhanced capacity and cycle stability(458.9 mAh g^(−1) at 0.2 A g^(−1) after 100 cycles),superior to those of commercial graphite.Benefiting from the self‐adaption of Sn dispersion,spent graphite with different degrees of defects can be regenerated to similar structures and performance.EverBatt analysis indicates that targeted regeneration and upcycling have significantly lower energy consumption(~99%reduction)and near‐zero CO_(2) emission,and yield much higher profit than hydrometallurgy,which opens a new avenue for direct upcycling of spend graphite in an efficient,green,and profitable manner for sustainable battery manufacture. 展开更多
关键词 battery recycling spent graphite targeted regeneration upcycling graphite
下载PDF
Air-Ground Collaborative Mobile Edge Computing:Architecture,Challenges,and Opportunities 被引量:1
7
作者 Qin Zhen He Shoushuai +5 位作者 Wang Hai Qu Yuben Dai Haipeng Xiong Fei Wei Zhenhua Li Hailong 《China Communications》 SCIE CSCD 2024年第5期1-16,共16页
By pushing computation,cache,and network control to the edge,mobile edge computing(MEC)is expected to play a leading role in fifth generation(5G)and future sixth generation(6G).Nevertheless,facing ubiquitous fast-grow... By pushing computation,cache,and network control to the edge,mobile edge computing(MEC)is expected to play a leading role in fifth generation(5G)and future sixth generation(6G).Nevertheless,facing ubiquitous fast-growing computational demands,it is impossible for a single MEC paradigm to effectively support high-quality intelligent services at end user equipments(UEs).To address this issue,we propose an air-ground collaborative MEC(AGCMEC)architecture in this article.The proposed AGCMEC integrates all potentially available MEC servers within air and ground in the envisioned 6G,by a variety of collaborative ways to provide computation services at their best for UEs.Firstly,we introduce the AGC-MEC architecture and elaborate three typical use cases.Then,we discuss four main challenges in the AGC-MEC as well as their potential solutions.Next,we conduct a case study of collaborative service placement for AGC-MEC to validate the effectiveness of the proposed collaborative service placement strategy.Finally,we highlight several potential research directions of the AGC-MEC. 展开更多
关键词 air-ground architecture COLLABORATIVE mobile edge computing
下载PDF
Step‑by‑Step Modulation of Crystalline Features and Exciton Kinetics for 19.2%Efficiency Ortho‑Xylene Processed Organic Solar Cells 被引量:1
8
作者 Bosen Zou Weiwei Wu +10 位作者 Top Archie Dela Pena Ruijie Ma Yongmin Luo Yulong Hai Xiyun Xie Mingjie Li Zhenghui Luo Jiaying Wu Chuluo Yang Gang Li He Yan 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第2期258-272,共15页
With plenty of popular and effective ternary organic solar cells(OSCs)construction strategies proposed and applied,its power conversion efficiencies(PCEs)have come to a new level of over 19%in single-junction devices.... With plenty of popular and effective ternary organic solar cells(OSCs)construction strategies proposed and applied,its power conversion efficiencies(PCEs)have come to a new level of over 19%in single-junction devices.However,previous studies are heavily based in chloroform(CF)leaving behind substantial knowledge deficiencies in understanding the influence of solvent choice when introducing a third component.Herein,we present a case where a newly designed asymmetric small molecular acceptor using fluoro-methoxylated end-group modification strategy,named BTP-BO-3FO with enlarged bandgap,brings different morphological evolution and performance improvement effect on host system PM6:BTP-eC9,processed by CF and ortho-xylene(o-XY).With detailed analyses supported by a series of experiments,the best PCE of 19.24%for green solvent-processed OSCs is found to be a fruit of finely tuned crystalline ordering and general aggregation motif,which furthermore nourishes a favorable charge generation and recombination behavior.Likewise,over 19%PCE can be achieved by replacing spin-coating with blade coating for active layer deposition.This work focuses on understanding the commonly met yet frequently ignored issues when building ternary blends to demonstrate cutting-edge device performance,hence,will be instructive to other ternary OSC works in the future. 展开更多
关键词 Organic solar cells Ternary design Solvent selection Flouro-methoxylated end group Morphological ordering
下载PDF
Ligand Engineering in Tin-Based Perovskite Solar Cells
9
作者 Peizhou Li Xiangrong Cao +9 位作者 Jingrui Li Bo Jiao Xun Hou Feng Hao Zhijun Ning Zuqiang Bian Jun Xi Liming Ding Zhaoxin Wu Hua Dong 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第10期112-150,共39页
Perovskite solar cells(PSCs)have attracted aggressive attention in the photovoltaic field in light of the rapid increasing power conversion efficiency.However,their large-scale application and commercialization are li... Perovskite solar cells(PSCs)have attracted aggressive attention in the photovoltaic field in light of the rapid increasing power conversion efficiency.However,their large-scale application and commercialization are limited by the toxicity issue of lead(Pb).Among all the lead-free perovskites,tin(Sn)-based perovskites have shown potential due to their low toxicity,ideal bandgap structure,high carrier mobility,and long hot carrier lifetime.Great progress of Sn-based PSCs has been realized in recent years,and the certified efficiency has now reached over 14%.Nevertheless,this record still falls far behind the theoretical calculations.This is likely due to the uncontrolled nucleation states and pronounced Sn(Ⅳ)vacancies.With insights into the methodologies resolving both issues,ligand engineering-assisted perovskite film fabrication dictates the state-of-the-art Sn-based PSCs.Herein,we summarize the role of ligand engineering during each state of film fabrication,ranging from the starting precursors to the ending fabricated bulks.The incorporation of ligands to suppress Sn~(2+)oxidation,passivate bulk defects,optimize crystal orientation,and improve stability is discussed,respectively.Finally,the remained challenges and perspectives toward advancing the performance of Sn-based PSCs are presented.We expect this review can draw a clear roadmap to facilitate Sn-based PSCs via ligand engineering. 展开更多
关键词 PEROVSKITE Solar cells LEAD-FREE Ligand engineering DEFECTS Stability
下载PDF
Surface Patterning of Metal Zinc Electrode with an In‑Region Zincophilic Interface for High‑Rate and Long‑Cycle‑Life Zinc Metal Anode 被引量:1
10
作者 Tian Wang Qiao Xi +8 位作者 Kai Yao Yuhang Liu Hao Fu Venkata Siva Kavarthapu Jun Kyu Lee Shaocong Tang Dina Fattakhova‑Rohlfing Wei Ai Jae Su Yu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第6期192-209,共18页
The undesirable dendrite growth induced by non-planar zinc(Zn)deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially im... The undesirable dendrite growth induced by non-planar zinc(Zn)deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially impede the practical application of rechargeable aqueous Zn metal batteries(ZMBs).Herein,we present a strategy for achieving a high-rate and long-cycle-life Zn metal anode by patterning Zn foil surfaces and endowing a Zn-Indium(Zn-In)interface in the microchannels.The accumulation of electrons in the microchannel and the zincophilicity of the Zn-In interface promote preferential heteroepitaxial Zn deposition in the microchannel region and enhance the tolerance of the electrode at high current densities.Meanwhile,electron aggregation accelerates the dissolution of non-(002)plane Zn atoms on the array surface,thereby directing the subsequent homoepitaxial Zn deposition on the array surface.Consequently,the planar dendrite-free Zn deposition and long-term cycling stability are achieved(5,050 h at 10.0 mA cm^(−2) and 27,000 cycles at 20.0 mA cm^(−2)).Furthermore,a Zn/I_(2) full cell assembled by pairing with such an anode can maintain good stability for 3,500 cycles at 5.0 C,demonstrating the application potential of the as-prepared ZnIn anode for high-performance aqueous ZMBs. 展开更多
关键词 Zn metal anode Surface patterning Directional Zn deposition Aqueous Zn-I_(2)batteries
下载PDF
Digital cancellation of multi-band passive inter-modulation based on Wiener-Hammerstein model
11
作者 Jinxiang Liu Xiaotao Zhang +1 位作者 Jun Yang Huiping Yang 《Digital Communications and Networks》 SCIE CSCD 2024年第4期1189-1197,共9页
Utilizing multi-band and multi-carrier techniques enhances throughput and capacity in Long-Term Evolution(LTE)-Advanced and 5G New Radio(NR)mobile networks.However,these techniques introduce Passive Inter-Modulation(P... Utilizing multi-band and multi-carrier techniques enhances throughput and capacity in Long-Term Evolution(LTE)-Advanced and 5G New Radio(NR)mobile networks.However,these techniques introduce Passive Inter-Modulation(PIM)interference in Frequency-Division Duplexing(FDD)systems.In this paper,a novel multi-band Wiener-Hammerstein model is presented to digitally reconstruct PIM interference signals,thereby achieving effective PIM Cancellation(PIMC)in multi-band scenarios.In the model,transmitted signals are independently processed to simulate Inter-Modulation Distortions(IMDs)and Cross-Modulation Distortions(CMDs).Furthermore,the Finite Impulse Response(FIR)filter,basis function generation,and B-spline function are applied for precise PIM product estimation and generation in multi-band scenarios.Simulations involving 4 carrier components from diverse NR frequency bands at varying transmitting powers validate the feasibility of the model for multi-band PIMC,achieving up to 19 dB in PIMC performance.Compared to other models,this approach offers superior PIMC performance,exceeding them by more than 5 dB in high transmitting power scenarios.Additionally,its lower sampling rate requirement reduces the hardware complexity associated with implementing multi-band PIMC. 展开更多
关键词 Passive inter-modulation Frequency-division duplexing Nonlinear distortion Digital cancellation Spline interpolation Wiener-Hammerstein model
下载PDF
Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom
12
作者 SHAIKH Abdul Hayee DANG Xiaoyu HUANG Daqing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2024年第1期81-93,共13页
Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteris... Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation accuracy.However,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for NCS.The TdisULAs structure generally consists of three ULAs,which are appropriately placed.The proposed antenna array approach fully exploits the non-circular characteristics of the sources.Given the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array competitors.Advantageously,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form expressions.Moreover,the proposed array also produces a filled resulting co-array.Numerical simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs. 展开更多
关键词 direction-of-arrival(DOA)estimation sparse array non-circular source(NCS) sum co-array difference co-array degrees of freedom(DOF)
下载PDF
An equivalent target plate damage probability calculation mathematics model and damage evaluation method
13
作者 Hanshan Li Xiaoqian Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第11期82-103,共22页
Aiming at the requirement of damage testing and evaluation of equivalent target plate based on the explosion of intelligent ammunition, this paper proposes a novel method for damage testing and evaluation method of ci... Aiming at the requirement of damage testing and evaluation of equivalent target plate based on the explosion of intelligent ammunition, this paper proposes a novel method for damage testing and evaluation method of circumferential equivalent target plate. Leveraging the dispersion characteristics parameters of fragment, we establish a calculation model of the fragment power situation and the damage calculation model under the condition of fragment ultimate penetration equivalent target plate. The damage model of equivalent target plate involves the fragment dispersion density, the local perforation damage criterion, the tearing damage model, and the damage probability. We use the camera to obtain the image of the equivalent target plate with fragment perforation, and research the algorithm of fragment distribution position recognition and fragment perforation area calculation method on the equivalent target plate by image processing technology. Based on the obtained parameters of the breakdown position and perforation area of fragments on equivalent target plate, we apply to damage calculation model of equivalent target plate, and calculate the damage probability of each equivalent target plate, and use the combined probabilistic damage calculation method to obtain the damage evaluation results of the circumferential equivalent target plate in an intelligent ammunition explosion experiment. Through an experimental testing, we verify the feasibility and rationality of the proposed damage evaluation method by comparison, the calculation results can reflect the actual damage effect of the equivalent target plate. 展开更多
关键词 Target damage evaluation Damage probability FRAGMENTS Equivalent target plate Image processing
下载PDF
Distributed IRS-Aided DF Relaying Systems:Performance Analysis and Optimization
14
作者 Sun Qiang Qian Panpan +3 位作者 Chen Xiaomin Ju Jinjuan Wang Jue Zhang Jiayi 《China Communications》 SCIE CSCD 2024年第6期129-145,共17页
Intelligent reflecting surface(IRS)is a newly emerged and promising paradigm to substantially improve the performance of wireless communications by constructing favorable communication channels via properly tuning mas... Intelligent reflecting surface(IRS)is a newly emerged and promising paradigm to substantially improve the performance of wireless communications by constructing favorable communication channels via properly tuning massive reflecting elements.This paper considers a distributed IRS aided decode-and-forward(DF)relaying system over Nakagami-m fading channels.Based on a tight approximation for the distribution of the received signalto-noise ratio(SNR),we first derive exact closed-form expressions of the outage probability,ergodic capacity,and energy efficiency for the considered system.Moreover,we propose the optimal IRS configuration considering the energy efficiency and pilot overhead.Finally,we compare the performance between the distributed IRS-aided DF relaying and multi-IRS-only systems,and verify the analytical results by using monte carlo simulations. 展开更多
关键词 CONFIGURATION energy efficiency ergodic capacity intelligent reflecting surface IRS outage probability
下载PDF
Fractional-order heterogeneous memristive Rulkov neuronal network and its medical image watermarking application
15
作者 丁大为 牛炎 +4 位作者 张红伟 杨宗立 王金 王威 王谋媛 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期306-314,共9页
This article proposes a novel fractional heterogeneous neural network by coupling a Rulkov neuron with a Hopfield neural network(FRHNN),utilizing memristors for emulating neural synapses.The study firstly demonstrates... This article proposes a novel fractional heterogeneous neural network by coupling a Rulkov neuron with a Hopfield neural network(FRHNN),utilizing memristors for emulating neural synapses.The study firstly demonstrates the coexistence of multiple firing patterns through phase diagrams,Lyapunov exponents(LEs),and bifurcation diagrams.Secondly,the parameter related firing behaviors are described through two-parameter bifurcation diagrams.Subsequently,local attraction basins reveal multi-stability phenomena related to initial values.Moreover,the proposed model is implemented on a microcomputer-based ARM platform,and the experimental results correspond to the numerical simulations.Finally,the article explores the application of digital watermarking for medical images,illustrating its features of excellent imperceptibility,extensive key space,and robustness against attacks including noise and cropping. 展开更多
关键词 fractional order MEMRISTORS Rulkov neuron medical image watermarking
下载PDF
Task Offloading and Resource Allocation in NOMA-VEC:A Multi-Agent Deep Graph Reinforcement Learning Algorithm
16
作者 Hu Yonghui Jin Zuodong +1 位作者 Qi Peng Tao Dan 《China Communications》 SCIE CSCD 2024年第8期79-88,共10页
Vehicular edge computing(VEC)is emerging as a promising solution paradigm to meet the requirements of compute-intensive applications in internet of vehicle(IoV).Non-orthogonal multiple access(NOMA)has advantages in im... Vehicular edge computing(VEC)is emerging as a promising solution paradigm to meet the requirements of compute-intensive applications in internet of vehicle(IoV).Non-orthogonal multiple access(NOMA)has advantages in improving spectrum efficiency and dealing with bandwidth scarcity and cost.It is an encouraging progress combining VEC and NOMA.In this paper,we jointly optimize task offloading decision and resource allocation to maximize the service utility of the NOMA-VEC system.To solve the optimization problem,we propose a multiagent deep graph reinforcement learning algorithm.The algorithm extracts the topological features and relationship information between agents from the system state as observations,outputs task offloading decision and resource allocation simultaneously with local policy network,which is updated by a local learner.Simulation results demonstrate that the proposed method achieves a 1.52%∼5.80%improvement compared with the benchmark algorithms in system service utility. 展开更多
关键词 edge computing graph convolutional network reinforcement learning task offloading
下载PDF
HetNets Under Decoupled Uplink and Downlink Access with UE Random Discontinuous Transmission: Local Delay and Energy Efficiency
17
作者 Zhang Yue Zheng Fuchun Luo Jingjing 《China Communications》 SCIE CSCD 2024年第3期205-216,共12页
Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discon... Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discontinuous transmission (DTX)at user equipment (UE) is adopted to reduce the interferencecorrelation across different time slots. By utilizingstochastic geometry, we analytically derive themean local delay and energy efficiency (EE) of an uplinkHetNet with UE random DTX scheme under theDUDA mode. These expressions are further approximatedas closed forms under reasonable assumptions.Our results reveal that under the DUDA mode, there isan optimal EE with respect to mute probability underthe finite local delay constraint. In addition, with thesame finite mean local delay as under the coupled uplinkand downlink access (CUDA) mode, the HetNetsunder the DUDA mode can achieve a higher EE witha lower mute probability. 展开更多
关键词 decoupled uplink and downlink access(DUDA) heterogeneous networks(HetNets) random discontinuous transmission(DTX) stochastic geometry
下载PDF
Nonlinear Seebeck and Peltier effects in a Majorana nanowire coupled to leads
18
作者 迟锋 刘佳 +2 位作者 付振国 刘黎明 易子川 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期547-552,共6页
We theoretically study nonlinear thermoelectric transport through a topological superconductor nanowire hosting Majorana bound states(MBSs) at its two ends, a system named as Majorana nanowire(MNW). We consider that t... We theoretically study nonlinear thermoelectric transport through a topological superconductor nanowire hosting Majorana bound states(MBSs) at its two ends, a system named as Majorana nanowire(MNW). We consider that the MNW is coupled to the left and right normal metallic leads subjected to either bias voltage or temperature gradient. We focus our attention on the sign change of nonlinear Seebeck and Peltier coefficients induced by mechanisms related to the MBSs, by which the possible existence of MBSs might be proved. Our results show that for a fixed temperature difference between the two leads, the sign of the nonlinear Seebeck coefficient(thermopower) can be reversed by changing the overlap amplitude between the MBSs or the system equilibrium temperature, which are similar to the cases in linear response regime. By optimizing the MBS–MBS interaction amplitude and system equilibrium temperature, we find that the temperature difference may also induce sign change of the nonlinear thermopower. For zero temperature difference and finite bias voltage, both the sign and magnitude of nonlinear Peltier coefficient can be adjusted by changing the bias voltage or overlap amplitude between the MBSs. In the presence of both bias voltage and temperature difference, we show that the electrical current at zero Fermi level and the states induced by overlap between the MBSs keep unchanged, regardless of the amplitude of temperature difference. We also find that the direction of the heat current driven by bias voltage may be changed by weak temperature difference. 展开更多
关键词 quantum dot nonlinear Seebeck coefficient Peltier coefficient Majorana bound states sign change
下载PDF
Event-based nonfragile state estimation for memristive recurrent neural networks with stochastic cyber-attacks and sensor saturations
19
作者 邵晓光 张捷 鲁延娟 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期126-135,共10页
This paper addresses the issue of nonfragile state estimation for memristive recurrent neural networks with proportional delay and sensor saturations. In practical engineering, numerous unnecessary signals are transmi... This paper addresses the issue of nonfragile state estimation for memristive recurrent neural networks with proportional delay and sensor saturations. In practical engineering, numerous unnecessary signals are transmitted to the estimator through the networks, which increases the burden of communication bandwidth. A dynamic event-triggered mechanism,instead of a static event-triggered mechanism, is employed to select useful data. By constructing a meaningful Lyapunov–Krasovskii functional, a delay-dependent criterion is derived in terms of linear matrix inequalities for ensuring the global asymptotic stability of the augmented system. In the end, two numerical simulations are employed to illustrate the feasibility and validity of the proposed theoretical results. 展开更多
关键词 memristor-based neural networks proportional delays dynamic event-triggered mechanism sensor saturations
下载PDF
CMMCAN:Lightweight Feature Extraction and Matching Network for Endoscopic Images Based on Adaptive Attention
20
作者 Nannan Chong Fan Yang 《Computers, Materials & Continua》 SCIE EI 2024年第8期2761-2783,共23页
In minimally invasive surgery,endoscopes or laparoscopes equipped with miniature cameras and tools are used to enter the human body for therapeutic purposes through small incisions or natural cavities.However,in clini... In minimally invasive surgery,endoscopes or laparoscopes equipped with miniature cameras and tools are used to enter the human body for therapeutic purposes through small incisions or natural cavities.However,in clinical operating environments,endoscopic images often suffer from challenges such as low texture,uneven illumination,and non-rigid structures,which affect feature observation and extraction.This can severely impact surgical navigation or clinical diagnosis due to missing feature points in endoscopic images,leading to treatment and postoperative recovery issues for patients.To address these challenges,this paper introduces,for the first time,a Cross-Channel Multi-Modal Adaptive Spatial Feature Fusion(ASFF)module based on the lightweight architecture of EfficientViT.Additionally,a novel lightweight feature extraction and matching network based on attention mechanism is proposed.This network dynamically adjusts attention weights for cross-modal information from grayscale images and optical flow images through a dual-branch Siamese network.It extracts static and dynamic information features ranging from low-level to high-level,and from local to global,ensuring robust feature extraction across different widths,noise levels,and blur scenarios.Global and local matching are performed through a multi-level cascaded attention mechanism,with cross-channel attention introduced to simultaneously extract low-level and high-level features.Extensive ablation experiments and comparative studies are conducted on the HyperKvasir,EAD,M2caiSeg,CVC-ClinicDB,and UCL synthetic datasets.Experimental results demonstrate that the proposed network improves upon the baseline EfficientViT-B3 model by 75.4%in accuracy(Acc),while also enhancing runtime performance and storage efficiency.When compared with the complex DenseDescriptor feature extraction network,the difference in Acc is less than 7.22%,and IoU calculation results on specific datasets outperform complex dense models.Furthermore,this method increases the F1 score by 33.2%and accelerates runtime by 70.2%.It is noteworthy that the speed of CMMCAN surpasses that of comparative lightweight models,with feature extraction and matching performance comparable to existing complex models but with faster speed and higher cost-effectiveness. 展开更多
关键词 Feature extraction and matching lightweighted network medical images ENDOSCOPIC ATTENTION
下载PDF
上一页 1 2 144 下一页 到第
使用帮助 返回顶部