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FSCIL-EACA: Few-Shot Class-Incremental Learning Network Based on Embedding Augmentation and Classifier Adaptation for Image Classification

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Chinese Journal of Electronics 2024年第1期33卷 139-152页

作者： Ruru ZHANG Haihong E Meina SONG School of Computer Science Beijing University of Posts and Telecommunications Education Department Information Network Engineering Research Center Beijing University of Posts and Telecommunications

The ability to learn incrementally is critical to the long-term operation of AI systems. Benefiting from the power of few-shot class-incremental learning(FSCIL), deep learning models can continuously recognize new classes with only a few samples. The difficulty is that limited instances of new classes will lead to overfitting and exacerbate the catastrophic forgetting of the old classes. Most previous works alleviate the above problems by imposing strong constraints on the model structure or parameters, but ignoring embedding network transferability and classifier adaptation(CA), failing to guarantee the efficient utilization of visual features and establishing relationships between old and new classes. In this paper, we propose a simple and novel approach from two perspectives: embedding bias and classifier bias. The method learns an embedding augmented(EA) network with cross-class transfer and class-specific discriminative abilities based on self-supervised learning and modulated attention to alleviate embedding bias. Based on the adaptive incremental classifier learning scheme to realize incremental learning capability,guiding the adaptive update of prototypes and feature embeddings to alleviate classifier bias. We conduct extensive experiments on two popular natural image datasets and two medical datasets. The experiments show that our method is significantly better than the baseline and achieves state-of-the-art results.

关键词： Training Adaptation models Visualization Image recognition Prototypes Self-supervised learning Power capacitors

Phase diagram and quench dynamics of a periodically drivenHaldane model

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Chinese Physics B 2024年第9期33卷 317-325页

作者： Minxuan Ren Han Yang Mingyuan Sun School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China

We investigate a periodically driven Haldane model subjected to a two-stage driving scheme in the form of a step *** using the Floquet theory,we obtain the topological phase diagram of the *** also find that anomalous Floquet topological phases exist in the *** on examining the quench dynamics among topological phases,we analyze the site distribution of the 0-mode and p-mode edge states in long-period evolution after a *** results demonstrate that,under certain conditions,the site distribution of the 0-mode can be confined at the edge even in long-period ***,both the 0-mode and p-mode can recover and become confined at the edge in long-period evolution when the post-quench parameters(T,M_(2) /M_(1))in the phase diagram cross away from the phase boundary (M_(2)/ M_(1))=(6√3t2)/ (M_(1)−***,we conclude that whether the edge state is confined at the edge in the long-period evolution after a quench depends on the similarity of the edge states before and after the *** findings reveal some new characteristics of quench dynamics in a periodically driven system.

关键词： Floquet system Haldane model quench dynamics topological phase diagram

Floquet spectrum and universal dynamics of a periodically driven two-atom system

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Chinese Physics B 2024年第2期33卷 436-443页

作者：谢文柱周正强李轩崔思淼孙明远 School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China

We investigate the Floquet spectrum and excitation properties of a two-ultracold-atom system with periodically driven interaction in a three-dimensional harmonic *** interaction between the atoms is changed by varying the s-wave scattering length in two ways,the cosine and the square-wave *** is found that as the driving frequency increases,the Floquet spectrum exhibits two main features for both modulations,the accumulating and the spreading of the quasienergy levels,which further lead to different dynamical *** accumulation is associated with collective excitations and the persistent growth of the energy,while the spread indicates that the energy is bounded at all *** initial scattering length,the driving frequency and amplitude can all significantly change the Floquet spectrum as well as the ***,the corresponding relation between them is valid ***,we propose a mechanism for selectively exciting the system to one specific state by using the avoided crossing of two quasienergy levels,which could guide preparation of a desired state in experiments.

关键词： Floquet spectrum universal dynamics two-atom system avoided crossing

Dual-band dynamic reconfigurable intelligent surface for signal enhancement in millimeter wave

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Science China(Technological Sciences) 2024年第4期67卷 1133-1138页

作者： YAO HuiMing DU XinRun WANG HengBin GAO Song PANG YaChen ZHENG HaiRong GONG HuiWen LI Yi XU JianChun ZHANG JianHua BI Ke State Key Laboratory of Information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China beijing Key Laboratory of Intelligent telecommunications Software and Multimedia Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

Millimeter wave with large bandwidth,high transmission rate,and low delay is considered a reliable alternative to cope with the spectrum ***,the fast attenuation and narrow beam characteristics make it difficult to achieve long-distance or wide-range ***,a 1-bit dual-band reflective reconfigurable intelligent surface(RIS)for signal enhancement in millimeter wave with 16×16 elements is designed,fabricated,and *** from most existent RIS,dynamic programming is realized at two separate frequency bands by integrating the PIN diodes and field-programmable gate array(FPGA).Particularly,the beam deflection,dual-beam,and multi-beam are created based on the coding theory and convolution operation,proving the effectiveness of wavefront ***,the far-field patterns and signal power with different coding sequences are measured and *** is indicated that the received signal power is 6–7 dB stronger than that without coding,which shows good agreement with the desired *** proposed reconfigurable metasurface exhibits great potential in beam forming,making it a promising candidate for progressive wireless communication applications.

关键词： dual-band millimeter wave reconfigurable intelligent surface signal enhancement

Ultralow-phase-noise and broadband frequency-hopping coupled optoelectronic oscillator under quiet point operation

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Photonics Research 2024年第8期12卷 1785-1793页

作者： HUI LIU MINGYANG GUO TIAN ZHANG JIAN DAI KUN XU State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave *** these,optoelectronic oscillators(OEOs)and coupled optoelectronic oscillators(COEOs)have demonstrated the capability to generate frequency-independent microwaves with exceptionally low phase ***,the tunability of the oscillators is rather limited due to the necessity for narrowband electronic bandpass filters,presenting challenges in achieving both wide and rapid tuning ***,we present a COEO featuring ultralow phase noise,flexible tuning capability,and high *** is achieved through a quiet point(QP)-operated harmonic mode-locked fiber laser,which effectively mitigates optical amplifier noise and supermode competition,thus significantly diminishing the necessity for ultra-narrow electronic *** to the liberated tuning ability,we present an oscillator that can be tuned from 2 GHz to 18 GHz,with phase noise as low as-140 d Bc/Hz at 10 k Hz under the QP *** then illustrate the practical application of the proposed oscillator in generating frequency-hopping signals with consistent spurious modes less than-85 d Bc,absolute phase noise below-135 d Bc/Hz at 10 k Hz,hopping resolution of 1.25 MHz,and fractional frequency stability below 6.1×10^(-12)at 1 s averaging time when locked to a *** presented COEO structure emerges as a compelling solution for agile and low-noise microwave sources in advanced wireless communication and radar systems.

关键词： optoelectronic tuning amplifier

A credibility-aware swarm-federated deep learning framework in internet of vehicles

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Digital Communications and Networks 2024年第1期10卷 150-157页

作者： Zhe Wang Xinhang Li Tianhao Wu Chen Xu Lin Zhang School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China

Although Federated Deep Learning(FDL)enables distributed machine learning in the Internet of Vehicles(IoV),it requires multiple clients to upload model parameters,thus still existing unavoidable communication overhead and data privacy *** recently proposed Swarm Learning(SL)provides a decentralized machine learning approach for unit edge computing and blockchain-based coordination.A Swarm-Federated Deep Learning framework in the IoV system(IoV-SFDL)that integrates SL into the FDL framework is proposed in this *** IoV-SFDL organizes vehicles to generate local SL models with adjacent vehicles based on the blockchain empowered SL,then aggregates the global FDL model among different SL groups with a credibility weights prediction *** experimental results show that compared with the baseline frameworks,the proposed IoV-SFDL framework reduces the overhead of client-to-server communication by 16.72%,while the model performance improves by about 5.02%for the same training iterations.

关键词： Swarm learning Federated deep learning Internet of vehicles Privacy Efficiency

Advanced development of grain boundaries in TMDs from fundamentals to hydrogen evolution application

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Chinese Chemical Letters 2024年第5期35卷 117-129页

作者： Ziyang Yin Lingbin Xie Weinan Yin Ting Zhi Kang Chen Junan Pan Yingbo Zhang Jingwen Li Longlu Wang College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Nanjing University of Posts&Telecommunications(NJUPT)Nanjing 210023China Institute of Advanced Materials(IAM)&Institute of Flexible Electronics(Future Technology) Nanjing University of Posts&Telecommunications(NJUPT)Nanjing 210023China

Grain boundary(GB),as a kind of lattice defect,widely exists in two-dimensional transition metal dichalcogenides(2D TMDs),which has complex and diverse influences on the physical/chemical properties of 2D *** are universally considered to be a double-edged sword,although some electrical and mechanical properties of 2D TMDs would be adversely affected leading to the reduced overall quality,certain structure-oriented applications could be realized based on its unique *** this review,we first detailed the atomic structure characteristics of GBs and the corresponding techniques,then we systematically summarized the methods of introducing GBs into 2D ***,we expounded unique electrical,mechanical,and chemical properties of the GBs in 2D TMDs and clarified its internal relationship with the atomic ***,the application of GB structure in hydrogen evolution reaction(HER)is also *** the end,we make a conclusion and put forward outlooks,hoping to further promote the basic research of GB and boost the wide application of 2D TMDs.

关键词： Grain boundary Transition metal dichalcogenides Two-dimensional materials Hydrogen evolution reaction Dislocation Molybdenum disulfide

LRChain:data protection and sharing method of learning archives based on consortium blockchain

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The Journal of China Universities of posts and telecommunications 2024年第4期31卷 28-42页

作者： Lan Lina Gao Yuhan Shi Ruisheng Wu Fenfen School of Humanities Beijing University of Posts and TelecommunicationsBeijing 100876China School of Cyberspace Security Beijing University of Posts and TelecommunicationsBeijing 100876China Key Laboratory of Trustworthy Distributed Computing and Service Beijing University of Posts and TelecommunicationsMinistry of EducationBeijing 100876China

Learning archives management in traditional systems faces challenges such as inadequate security,weak tamper resistance,and limited sharing *** address these issues,this paper proposes LRChain,a method based on consortium blockchain,for lifelong learning archives data protection and *** employs a combination of on-chain and off-chain cooperative storage using a consortium chain and inter planetary file system(IPFS)to enhance data security and *** also enables fine-grained verification of learning archives through selective disclosure principles,ensuring privacy protection of sensitive ***,an attributebased encryption(ABE)algorithm is utilized to establish authorized access control for learning archives,facilitating safe and trusted *** evaluations and security analyses demonstrate that this method exhibits decentralization,strong security,tamper resistance,and performs well,effectively meeting the requirements for secure sharing of learning archive data.

关键词： learning archives consortium blockchain collaborative storage secure sharing

Improved Twin Support Vector Machine Algorithm and Applications in Classification Problems

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China Communications 2024年第5期21卷 261-279页

作者： Sun Yi Wang Zhouyang beijing university of posts and telecommunications School of Computer Science(National Pilot Software Engineering School) beijing university of posts and telecommunications International School

The distribution of data has a significant impact on the results of *** the distribution of one class is insignificant compared to the distribution of another class,data imbalance *** will result in rising outlier values and ***,the speed and performance of classification could be greatly *** the above problems,this paper starts with the motivation and mathematical representing of classification,puts forward a new classification method based on the relationship between different classification *** with the vector characteristics of the actual problem and the choice of matrix characteristics,we firstly analyze the orderly regression to introduce slack variables to solve the constraint problem of the lone *** we introduce the fuzzy factors to solve the problem of the gap between the isolated points on the basis of the support vector *** introduce the cost control to solve the problem of sample ***,based on the bi-boundary support vector machine,a twostep weight setting twin classifier is *** can help to identify multitasks with feature-selected patterns without the need for additional optimizers,which solves the problem of large-scale classification that can’t deal effectively with the very low category distribution gap.

关键词： fuzzy ordered regression(OR) relaxing variables twin support vector machine