检索结果-南通市图书馆

Fixed-Time Gradient Flows for Solving Constrained Optimization: A Unified Approach

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1849-1864页

作者： Xinli Shi Xiangping Xu Guanghui Wen Jinde Cao School of Cyber Science and Engineering Southeast UniversityNanjing 210096China School of Mathematics Southeast UniversityNanjing 210096China

The accelerated method in solving optimization problems has always been an absorbing *** on the fixedtime(FxT)stability of nonlinear dynamical systems,we provide a unified approach for designing FxT gradient flows(FxTGFs).First,a general class of nonlinear functions in designing FxTGFs is provided.A unified method for designing first-order FxTGFs is shown under Polyak-Łjasiewicz inequality assumption,a weaker condition than strong *** there exist both bounded and vanishing disturbances in the gradient flow,a specific class of nonsmooth robust FxTGFs with disturbance rejection is *** the strict convexity assumption,Newton-based FxTGFs is given and further extended to solve time-varying ***,the proposed FxTGFs are further used for solving equation-constrained ***,an FxT proximal gradient flow with a wide range of parameters is provided for solving nonsmooth composite *** show the effectiveness of various FxTGFs,the static regret analyses for several typical FxTGFs are also provided in ***,the proposed FxTGFs are applied to solve two network problems,i.e.,the network consensus problem and solving a system linear equations,respectively,from the perspective of ***,by choosing component-wisely sign-preserving functions,these problems can be solved in a distributed way,which extends the existing *** accelerated convergence and robustness of the proposed FxTGFs are validated in several numerical examples stemming from practical applications.

关键词： Consensus constrained optimization disturbance rejection linear equations fixed-time gradient flow(FxTGF).

维普期刊数据库

A comprehensive analysis of DAC-SDC FPGA low power object detection challenge

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第8期67卷 300-320页

作者： Jingwei ZHANG Guoqing LI Meng ZHANG Xinye CAO Yu ZHANG Xiang LI Ziyang CHEN Jun YANG School of Electronics Science and Engineering Southeast University

The lower power object detection challenge(LPODC) at the IEEE/ACM Design Automation Conference is a premier contest in low-power object detection and algorithm(software)-hardware co-design for edge artificial intelligence, which has been a success in the past five years. LPODC focused on designing and implementing novel algorithms on the edge platform for object detection in images taken from unmanned aerial vehicles(UAVs), which attracted hundreds of teams from dozens of countries to participate. Our team SEUer has been participating in this competition for three consecutive years from 2020 to 2022 and obtained sixth place respectively in 2020 and 2021. Recently, we achieved the championship in 2022. In this paper, we presented the LPODC for UAV object detection from 2018 to 2022, including the dataset, hardware platform,and evaluation method. In addition, we also introduced and discussed the details of methods proposed by each year's top three teams from 2018 to 2022 in terms of network, accuracy, quantization method, hardware performance, and total score. Additionally, we conducted an in-depth analysis of the selected entries and results, along with summarizing representative methodologies. This analysis serves as a valuable practical resource for researchers and engineers in deploying the UAV application on edge platforms and enhancing its feasibility and reliability. According to the analysis and discussion, it becomes evident that the adoption of a hardware-algorithm co-design approach is paramount in the context of tiny machine learning(TinyML).This approach surpasses the mere optimization of software and hardware as separate entities, proving to be essential for achieving optimal performance and efficiency in TinyML applications.

关键词： tiny machine learning object detection convolutional neural networks algorithm-hardware co-design low power field programmable gate array

Macroscopic model and statistical model to characterize electromagnetic information of a digital coding metasurface

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第3期11卷 159-171页

作者： Rui Wen Shao Jun Wei Wu Zheng Xing Wang Hui Xu Han Qing Yang Qiang Cheng Tie Jun Cui Institute of Electromagnetic Space Southeast University State Key Laboratory of Millimeter Waves Southeast University Peng Cheng Laboratory Pazhou Laboratory(Huangpu)

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems.

关键词： electromagnetic information theory current entropy current space digital coding metasurface macroscopic model statistical model

An externally perceivable smart leaky-wave antenna based on spoof surface plasmon polaritons

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2024年第9期7卷 5-20页

作者： Weihan Li Jia Chen Shizhao Gao Lingyun Niu Jiaxuan Wei Ruosong Sun Yaqi Wei Wenxuan Tang Tie Jun Cui State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China Institute of Electromagnetic Space Southeast UniversityNanjing 210096China

Smart antennas have received great attention for their potentials to enable communication and perception functions at the same ***,realizing the function synthesis remains an open challenge,and most existing system solutions are limited to narrow operating bands and high complexity and ***,we propose an externally perceivable leakywave antenna(LWA)based on spoof surface plasmon polaritons(SSPPs),which can realize adaptive real-time switching between the“radiating”and“non-radiating”states and beam tracking at different *** the assistance of computer vision,the smart SSPP-LWA is able to detect the external target user or jammer,and intelligently track the target by self-adjusting the operating *** proposed scheme helps to reduce the power consumption through dynamically controlling the radiating state of the antenna,and improve spectrum utilization and avoid spectrum conflicts through intelligently deciding the radiating *** the other hand,it is also helpful for the physical layer communication security through switching the antenna working state according to the presence of the target and target beam tracking in real *** addition,the proposed smart antenna can be generalized to other metamaterial systems and could be a candidate for synaesthesia integration in future smart antenna systems.

关键词： smart antenna external perception spoof surface plasmon polaritons computer vision aids

Effect of Epoxy Resin on the Properties of Recycled Asphalt

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 Wuhan university of Technology(Materials Science) 2024年第5期39卷 1149-1155页

作者： YANG Ruochong CHEN Huimin YANG Jun School of Transportation Southeast UniversityNanjing 211189China

To promote the recycling of reclaimed asphalt pavement(RAP),epoxy resin was used to prepare the epoxy-recycled asphalt *** effect of epoxy resin on the properties of aged asphalt binder was investigated based on the tensile test,flexural creep test,and laser scanning confocal *** curing characteristics and the mechanical performance of recycled asphalt with different epoxy contents were *** results show that the low-temperature performance,ductility,and strength of the aged asphalt binder were significantly improved when the epoxy content reached 40%.The curing time of epoxy-recycled asphalt should be at least 4 d to ensure the formation of good internal spatial network structure.

关键词： RAP epoxy resin aged asphalt mechanical performance

维普期刊数据库

A technical survey on mechanism and influence factors for asphalt pavement skid-resistance

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第5期12卷 845-868页

作者： Xiyin LIU Haoyuan LUO Can CHEN Leyi ZHU Siyu CHEN Tao MA Xiaoming HUANG School of Transportation Southeast UniversityNanjing211189China

To explore the research status on mechanism of the skid-resistance for asphalt pavement, the related achievements of the rubber friction, the tire–road contact, and the influence factors were reviewed. The rubber friction was reviewed from the mechanism and rubber friction model. The tire-road contact was studied from the modeling methods, the evaluation methods, and the skid-resistance mechanisms at different conditions. The influence factors of skid-resistance were summarized from different designing processes. This review showed that the appropriate contact or evaluation model should be selected according to the required parameters. Although the finite element method is widely used, the accuracy of the model, the boundary conditions, and the load cases need to be further improved. The optimized aggregates and asphalt binders, reasonable gradation, reasonable geometric design, and strict construction quality control are necessary for good initial skid-resistance. Pavement texture as an important factor affecting skid-resistance should be considered in pavement gradation design, especially for wearing layer technology.

关键词： asphalt pavement rubber friction tire-road contact skid-resistance

Study on macro and micro shear strength of continuously graded and gap-graded sand

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第3期86卷 101-116页

作者： Peiran Zhao Songyu Liu Kai Wu School of Transportation Southeast UniversityNanjing210096China

The particle gradation of sand has a significant influence on its shear strength,yet the similarities and differences between the effects of continuous and gap grading have yet to be fully *** this study,the discrete element method(DEM)was used to simulate biaxial tests on granular samples that were both continuously graded and *** macroscopic analysis revealed that the shear strength of continuously graded sands increases initially and then decreases as the uniformity of particle size distribution *** the other hand,the lack of medium particles in gap-graded sands amplifies the difference in particle size between coarse and fine particles,leading to a decrease in shear ***,both continuous and gap gradings affect the internal packing structure of the particle assembly,which consequently affects particle stress distributions,contact forces,coordination numbers,stress-induced anisotropies,and contact force networks,thus having an impact on the macroscopic shear *** global uniformity of particle size distribution was unidirectionally affected by continuous grading,while gap grading had a locally bidirectional *** findings provide a better understanding of the effects of particle grading on the macroscopic shear strength of sands.

关键词： Biaxial test Shear strength Particle gradation Discrete element method Micromechanics

Optimal Operation Strategy Analysis with Scenario Generation Method Based on Principal Component Analysis,Density Canopy,and K-medoids for Integrated Energy 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 Modern Power Systems and Clean Energy 2024年第1期12卷 89-100页

作者： Bingtuan Gao Yunyu Zhu Yuanmei Li School of Electrical Engineering Southeast UniversityNanjingChina

The operation of integrated energy systems(IESs)is confronted with great challenges for increasing penetration rate of renewable energy and growing complexity of energy *** generation is one of ordinary methods to alleviate the system uncertainties by extracting several typical scenarios to represent the original high-dimensional *** paper proposes a novel representative scenario generation method based on the feature extraction of panel *** original high-dimensional data are represented by an aggregated indicator matrix using principal component analysis to preserve temporal ***,the aggregated indicator matrix is clustered by an algorithm combining density canopy and *** with the proposed scenario generation method,an optimal operation model of IES is established,where the objective is to minimize the annual operation costs considering carbon trading ***,case studies based on the data of Aachen,Germany in 2019 are *** results indicate that the adjusted rand index(ARI)and silhouette coefficient(SC)of the proposed method are 0.6153 and 0.6770,respectively,both higher than the traditional methods,namely K-medoids,K-means++,and density-based spatial clustering of applications with noise(DBSCAN),which means the proposed method has better *** error between optimal operation results of the IES obtained by the proposed method and all-year time series benchmark value is 0.1%,while the calculation time is reduced from 11029 s to 188 s,which verifies that the proposed method can be used to optimize operation strategy of IES with high efficiency without loss of accuracy.

关键词： Scenario generation principal component analysis(PCA) density canopy K-medoids integrated energy system

维普期刊数据库

Investigation of surface textures deterioration on pavement skid-resistance using hysteresis friction models and numerical simulation method

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 745-779页

作者： Haoyuan LUO Siyu CHEN Leyi ZHU Xiyin LIU Yangzezhi ZHENG Runming ZHAO Xiaoming HUANG School of Transportation Southeast UniversityNanjing 211189China National Demonstration Center for Experimental Education of Road and Traffic Engineering Southeast UniversityNanjing 211189China

Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface ***,these methods are difficult to be implemented in the analysis of situations with multi-factor coupling and some extreme *** study developed a framework to evaluate the skid-resistance deterioration of asphalt *** this framework,the portable laser scanning was used to create the digital worn pavement model,and a hydroplaning finite element(FE)model for these digital worn pavements was constructed to evaluate coupling effects of the texture evolution and factors of slip ratio,slip angle,velocity and water film on braking-cornering characteristics of *** this study,the deterioration of skid-resistance of five typical asphalt pavements due the surface texture wear was systematically investigated by this *** with previous works,this study established the rubber friction models for each digital worn pavement considering the energy hysteresis of rubber and the power spectrum density of surface *** the rubber friction model was used to define the interaction behaviors between the tire and corresponding wore pavements in the FE hydroplaning model,rather than using an empirical friction model or a fixed friction coefficient.

关键词： worn pavement skid-resistance friction coefficient textures evolution water film computer numerical simulation