检索结果-南通市图书馆

Underwater wireless optical NOMA communication experiment system exploiting GaN-based micro-LED array grouping

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第3期22卷 1-6页

作者：梁彦军殷洪玺黄安季秀阳王建英 School of information and communication engineering Dalian University of TechnologyDalian 116024China

This paper has proposed an experimental system for non-orthogonal multiple access(NOMA)wireless optical communication in challenging underwater turbulent environments,employing the gallium nitride(GaN)-based micro-LED *** design of the GaN-based micro-LED array enables the independent transmission of signals from distinct data streams within the NOMA framework,facilitating direct optical power-domain superposition of NOMA *** experimental setup involves emulating oceanic turbulence channels,characterized by varying the level of scintillation intensity,to thoroughly investigate the bit error rate(BER)*** outcomes unequivocally demonstrate the superiority of our proposed NOMA scheme,as compared to conventional circuit-driven optical NOMA systems utilizing fixed LED array grouping,particularly in the presence of turbulent underwater *** proposed NOMA scheme exhibits consistently superior BER performance and maintains excellent linearity at the lower frequencies while effectively mitigating signal distortion at the higher frequencies.

关键词： optical non-orthogonal multiple access gallium nitride-based micro-LED array oceanic turbulence channels bit error rate

Real-time UWOC miniaturized system based on FPGA and LED arrays and its application in MIMO

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第2期22卷 70-75页

作者：黄安殷洪玺梁彦军王建英沈众卫 School of information and communication engineering Dalian University of TechnologyDalian 116024China

In order to alleviate the impact of turbulence on the performance of underwater wireless optical communication(UWOC)in real time,and achieve high-speed real-time transmission and low cost and miniaturization of equipment,a 2×2 real-time multiple-input and multiple-output(MIMO)high-speed miniaturized UWOC system based on a field-programmable gate array(FPGA)and a high-power light-emitting diode(LED)array is designed in this *** terms of multiplexing gain,the imaging MIMO spatial multiplexing and high-order modulation for the first time are combined and the real-time high-speed transmission of PAM-4 signal based on the LED array light source in 12 m underwater channel at 100 Mbps rate is implemented,which effectively improves the throughput of the UWOC system with a high-power commercial LED light *** light of diversity gain,the system employs the diversity of repeated coding scheme to receive two identical non-return-to-zero on-off keying(NRZ-OOK)signals,which can compensate the fading or flickering sublinks in real time under the bubble-like simulated turbulence condition,and has high *** our knowledge,this is the first instance of a high rate and long-distance implementation of a turbulence-resistant real-time MIMO miniaturized UWOC system based on FPGA and high-power LED *** spatial diversity or spatial multiplexing capabilities,its low cost,integrity,and high robustness provide the system with important practical prospects.

关键词： underwater wireless optical communication MIMO spatial diversity spatial multiplexing

Rapid Phase Ambiguity Elimination Methods for DOA Estimator via Hybrid Massive MIMO Receive Array

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 175-184页

作者： Xichao ZHAN Zhongwen SUN Feng SHU Yiwen CHEN Xin CHENG Yuanyuan WU Qi ZHANG Yifan LI Peng ZHANG School of information and communication engineering Hainan University School of Electronic and Optical engineering Nanjing University of Science and Technology

For a sub-connected hybrid multiple-input multiple-output(MIMO) receiver with K subarrays and N antennas, there exists a challenging problem of how to rapidly remove phase ambiguity in only single time-slot. A direction of arrival(DOA) estimator of maximizing received power(Max-RP) is proposed to find the maximum value of K-subarray output powers, where each subarray is in charge of one sector, and the center angle of the sector corresponding to the maximum output is the estimated true DOA. To make an enhancement on precision, Max-RP plus quadratic interpolation(Max-RP-QI) method is designed. In the proposed Max-RP-QI, a quadratic interpolation scheme is adopted to interpolate the three DOA values corresponding to the largest three receive powers of *** achieve the Cramer Rao lower bound, a Root-MUSIC plus Max-RP-QI scheme is developed. Simulation results show that the proposed three methods eliminate the phase ambiguity during one time-slot and also show low computational complexities. The proposed Root-MUSIC plus Max-RP-QI scheme can reach the Cramer Rao lower bound,and the proposed Max-RP and Max-RP-QI are still some performance losses 2–4 d B compared to the Cramer Rao lower bound.

关键词： Phased arrays Interpolation Wireless sensor networks Direction-of-arrival estimation Simulation Receiving antennas Massive MIMO

Masked Autoencoders as Single Object Tracking Learners

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7期80卷 1105-1122页

作者： Chunjuan Bo XinChen Junxing Zhang School of information and communication engineering Dalian Minzu UniversityDalian116600China School of information and communication engineering Dalian University of TechnologyDalian116024China

Significant advancements have beenwitnessed in visual tracking applications leveragingViT in recent years,mainly due to the formidablemodeling capabilities of Vision Transformer(ViT).However,the strong performance of such trackers heavily relies on ViT models pretrained for long periods,limitingmore flexible model designs for tracking *** address this issue,we propose an efficient unsupervised ViT pretraining method for the tracking task based on masked autoencoders,called *** pretraining,we employ two shared-parameter ViTs,serving as the appearance encoder and motion encoder,*** appearance encoder encodes randomly masked image data,while the motion encoder encodes randomly masked pairs of video ***,an appearance decoder and a motion decoder separately reconstruct the original image data and video frame data at the pixel *** this way,ViT learns to understand both the appearance of images and the motion between video frames *** results demonstrate that ViT-Base and ViT-Large models,pretrained with TrackMAE and combined with a simple tracking head,achieve state-of-the-art(SOTA)performance without additional ***,compared to the currently popular MAE pretraining methods,TrackMAE consumes only 1/5 of the training time,which will facilitate the customization of diverse models for *** instance,we additionally customize a lightweight ViT-XS,which achieves SOTA efficient tracking performance.

关键词： Visual object tracking vision transformer masked autoencoder visual representation learning

Scale effect removal and range migration correction for hypersonic target coherent detection

维普期刊数据库评论

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 Systems engineering and Electronics 2024年第1期35卷 14-23页

作者： WU Shang SUN Zhi JIANG Xingtao ZHANG Haonan DENG Jiangyun LI Xiaolong CUI Guolong School of information and communication engineering University of Electronic Science and Technology of ChinaChengdu 611731China

The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar ***,with the increasing requirement of far-range detection,the time bandwidth product,which is corresponding to radar’s mean power,should be promoted in actual ***,the echo signal generates the scale effect(SE)at large time bandwidth product situation,influencing the intra and inter pulse integration *** eliminate SE and correct RM,this paper proposes an effective algorithm,i.e.,scaled location rotation transform(ScLRT).The ScLRT can remove SE to obtain the matching pulse compression(PC)as well as correct RM to complete CI via the location rotation transform,being implemented by seeking the actual rotation *** to the traditional coherent detection algorithms,Sc LRT can address the SE problem to achieve better detection/estimation *** last,this paper gives several simulations to assess the viability of ScLRT.

关键词： hypersonic target detection coherent integration(CI) scale effect(SE)removal range migration(RM)correction scaled location rotation transform(ScLRT)

On-chip spiking neural networks based on add-drop ring microresonators and electrically reconfigurable phase-change material photonic switches

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2024年第4期12卷 755-766页

作者： QIANG ZHANG NING JIANG YIQUN ZHANG ANRAN LI HUANHUAN XIONG GANG HU YONGSHENG CAO KUN QIU School of information and communication engineering University of Electronic Science and Technology of ChinaChengdu 611731China

We propose and numerically demonstrate a photonic computing primitive designed for integrated spiking neural networks (SNNs) based on add-drop ring microresonators (ADRMRs) and electrically reconfigurable phasechange material (PCM) photonic switches. In this neuromorphic system, the passive silicon-based ADRMR,equipped with a power-tunable auxiliary light, effectively demonstrates nonlinearity-induced dual neural dynamics encompassing spiking response and synaptic plasticity that can generate single-wavelength optical neural spikes with synaptic weight. By cascading these ADRMRs with different resonant wavelengths, weighted multiple-wavelength spikes can be feasibly output from the ADRMR-based hardware arrays when external wavelengthaddressable optical pulses are injected;subsequently, the cumulative power of these weighted output spikes is utilized to ascertain the activation status of the reconfigurable PCM photonic switches. Moreover, the reconfigurable mechanism driving the interconversion of the PCMs between the resonant-bonded crystalline states and the covalent-bonded amorphous states is achieved through precise thermal modulation. Drawing from the thermal properties, an innovative thermodynamic leaky integrate-and-firing (TLIF) neuron system is proposed. With the TLIF neuron system as the fundamental unit, a fully connected SNN is constructed to complete a classic deep learning task:the recognition of handwritten digit patterns. The simulation results reveal that the exemplary SNN can effectively recognize 10 numbers directly in the optical domain by employing the surrogate gradient algorithm. The theoretical verification of our architecture paves a whole new path for integrated photonic SNNs, with the potential to advance the field of neuromorphic photonic systems and enable more efficient spiking information processing.

关键词： neural networks precise

Seamless Indoor-Outdoor Switching Localization Algorithm based on CKF

在线全文

学校读者我要写书评

暂无评论

Journal of communications and information Networks 2024年第1期9卷 88-98页

作者： Gang Yang Guodong Hou Ningning Feng Weida Meng School of communication and information engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China

To solve the problem of large positioning error and discontinuous positioning of special forces members when moving in cross-region indoors and outdoors, and to compensate for the linearization error and local convergence problem that may exist in the extended Kalman filter(EKF)in nonlinear systems, that is,the iterative results may be trapped in a local optimum situation, a seamless indoor-outdoor switching localization algorithm based on cubature Kalman filter (CKF) is proposed. CKF does not require the computation of Jacobian matrices, which can improve computational efficiency and filtering accuracy to a certain extent. In the system, an inertial measurement unit (IMU) is employed to correct the positioning errors of ultra-wideband (UWB)and BeiDou navigation satellite system(BDS).The positioning data from UWB and BeiDou in cross-region are weighted fused and then fused with the data from the IMU using CKF to obtain the final accurate positioning information. This study designs a scene-switching mechanism to achieve seamless switching between indoor and outdoor positioning scenes. By jointly analyzing the positioning accuracy of UWB and BeiDou,the positioning scene is determined, and appropriate counting thresholds are set to avoid frequent erroneous scene switches. Experimental results show that the proposed algorithm achieves a positioning accuracy of approximately 21.7 cm in cross-region,which can enable seamless integration of indoor and outdoor positioning,avoid positioning jumps, and enhance positioning accuracy.

关键词： cubature Kalman filtering ultra-wideband inertial measurement unit fusion positioning seamless switching

Research on human gait sensing based on triboelectric nanogenerator

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nanotechnology and Precision engineering 2024年第2期7卷 32-40页

作者： Gang Yang Lifang Wang Jiayun Tian School of communication and information engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China

To address the problem of frequent battery replacement for wearable sensors applied to fall detection among the elderly,a portable and lowcost triboelectric nanogenerator(TENG)-based self-powered sensor for human gait monitoring is *** main fabrication materials of the TENG are polytetrafluoroethylene(PTFE)film,aluminum(Al)foil,and polyimide(PI)film,where PTFE and Al are the friction layer materials and the PI film is used to improve the output *** the ability of TENGs to monitor changes in environmental conditions,a self-powered sensor based on the TENG is placed in an insole to collect gait *** a TENG does not require a power source to convert physical and mechanical signals into electrical signals,the electrical signals can be used as sensing signals to be analyzed by a computer to recognize daily human activities and fall *** results show that the accuracy of the TENG-based sensor for recognizing human gait is 97.2%,demonstrating superior sensing performance and providing valuable insights for future monitoring of fall events in the elderly population.

关键词： Triboelectric nanogenerator Sensor Gait monitoring

Mutual information Maximization via Joint Power Allocation in Integrated Sensing and communications System

在线全文

学校读者我要写书评

暂无评论

China communications 2024年第2期21卷 129-142页

作者： Jia Zhu Junsheng Mu Yuanhao Cui Xiaojun Jing School of information and communication engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

In this paper, we focus on the power allocation of Integrated Sensing and communication(ISAC) with orthogonal frequency division multiplexing(OFDM) waveform. In order to improve the spectrum utilization efficiency in ISAC, we propose a design scheme based on spectrum sharing, that is,to maximize the mutual information(MI) of radar sensing while ensuring certain communication rate and transmission power constraints. In the proposed scheme, three cases are considered for the scattering off the target due to the communication signals,as negligible signal, beneficial signal, and interference signal to radar sensing, respectively, thus requiring three power allocation schemes. However,the corresponding power allocation schemes are nonconvex and their closed-form solutions are unavailable as a consequence. Motivated by this, alternating optimization(AO), sequence convex programming(SCP) and Lagrange multiplier are individually combined for three suboptimal solutions corresponding with three power allocation schemes. By combining the three algorithms, we transform the non-convex problem which is difficult to deal with into a convex problem which is easy to solve and obtain the suboptimal solution of the corresponding optimization problem. Numerical results show that, compared with the allocation results of the existing algorithms, the proposed joint design algorithm significantly improves the radar performance.

关键词： coexistence communications multicarrier radar mutual information spectrum sharing