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A Hybrid Feature Fusion Traffic Sign Detection Algorithm Based on YOLOv7

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Computers, Materials & Continua 2024年第7期80卷 1425-1440页

作者： Bingyi ren Juwei Zhang Tong Wang School of Mechanical Engineering Henan University of Science and TechnologyLuoyang471000China School of Information Engineering Henan University of Science and TechnologyLuoyang471000China School of Electronic Information Zhengzhou Institute of Aeronautical Industry ManagementZhengzhou450046China Henan Province New Energy Vehicle Power Electronics and Power Transmission Engineering Research Center Luoyang471000China

Autonomous driving technology has entered a period of rapid development,and traffic sign detection is one of the important *** target detection networks are difficult to adapt to scenarios where target sizes are seriously imbalanced,and traffic sign targets are small and have unclear features,which makes detection more ***,we propose aHybrid Feature Fusion Traffic Sign detection algorithmbased onYOLOv7(HFFTYOLO).First,a self-attention mechanism is incorporated at the end of the backbone network to calculate feature interactions within scales;Secondly,the cross-scale fusion part of the neck introduces a bottom-up multi-path fusion *** reuse paths at the end of the neck,paying particular attention to cross-scale fusion of highlevel *** addition,we found the appropriate channel width through a lot of experiments and reduced the superfluous *** terms of training,a newregression lossCMPDIoUis proposed,which not only considers the problem of loss degradation when the aspect ratio is the same but the width and height are different,but also enables the penalty term to dynamically change at different ***,our proposed improved method shows excellent results on the TT100K *** with the baseline model,without increasing the number of parameters and computational complexity,AP0.5 and AP increased by 2.2%and 2.7%,respectively,reaching 92.9%and 58.1%.

关键词： Small target detection YOLOv7 traffic sign detection regression loss

Spontaneous Infection and Periodic Evolving of Domain in a Diffusive SIS Epidemic Model

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 164-191页

作者： Qiang Wen Guo-qiang ren Bin Liu School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan430074China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan430074China

In this paper, we consider a susceptible-infective-susceptible(SIS) reaction-diffusion epidemic model with spontaneous infection and logistic source in a periodically evolving domain. Using the iterative technique,the uniform boundedness of solution is established. In addition, the spatial-temporal risk index R0(ρ) depending on the domain evolution rate ρ(t) as well as its analytical properties are discussed. The monotonicity of R0(ρ)with respect to the diffusion coefficients of the infected dI, the spontaneous infection rate η(ρ(t)y) and interval length L is investigated under appropriate conditions. Further, the existence and asymptotic behavior of periodic endemic equilibria are explored by upper and lower solution method. Finally, some numerical simulations are presented to illustrate our analytical results. Our results provide valuable information for disease control and prevention.

关键词： diffusive SIS model spontaneous infection periodically evolving domain periodic endemic equilibrium

Energy and exergy analyses and optimizations for two-stage TEC driven by two-stage TEG with Thomson effect

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Science China(Technological Sciences) 2024年第4期67卷 1077-1093页

作者： CHEN LinGen GE YanLin FENG HuiJun ren TingTing Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

Based on the non-equilibrium thermodynamics and energy and exergy analyses,a thermodynamic model of two-stage thermoelectric(TE)cooler(TTEC)driven by two-stage TE generator(TTEG)(TTEG-TTEC)combined TE device is established with involving Thomson effect by fitting method of variable physical parameters of TE *** total number of TE elements as constraint,influences of number distributions of TE elements on three device performance indictors,that is,cooling load,maximum COP and maximum exergetic efficiency,are *** number distributions of TE elements are optimized with three maximum performance indictors as the objectives,*** of hot-junction temperature of TTEG and coldjunction temperature of TTEC on optimization results are analyzed,and difference between optimization results corresponding to three performance indicators are *** performance intervals and optimal variable intervals are *** of Thomson effect on three general performance indicators,three optimal performance indicators and optimal variables are comparatively *** effect reduces three general performance indicators and three optimal performance indicators of *** hot-and cold-junction temperatures of TTEG and TTEC are 450,305,325 and 295 K,respectively,Thomson effect reduced maximum cooling load,maximum COP and maximum exergetic efficiency from 9.528 W,9.043×10^(-2)and2.552%to 6.651 W,6.286×10^(-2)and 1.752%,respectively.

关键词： non-equilibrium thermodynamics cooling load COP exergetic efficiency combined thermoelectric device performance optimization

Empirical model of concrete block fragment behavior under explosion loads

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Science China(Technological Sciences) 2024年第8期67卷 2515-2529页

作者： YANG Shuai NING JianGuo ren HuiLan XU XiangZhao State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing 100081China

Concrete structures undergo integral fragmentation under explosion loads. The fragmentation degree and particle-size distribution of concrete blocks under explosion loads must be considered during mining to ensure safety. In this study, the impulse is calculated based on the relationship between overpressure and time, and the impact energy of the explosion wave is obtained based on blast theory. Subsequently, the Mohr-Coulomb shear strength fracture criterion is introduced to determine the ultimate shear stress of the concrete materials, and an empirical model that can effectively calculate the energy consumption of concrete blocks under explosion loads is established. Furthermore, concrete fragments with different particle sizes under explosion scenarios are quantitatively predicted with the principle of energy conservation. Finally, explosion tests with different top standoff distances are conducted, and the concrete fragments after the explosion tests are recovered, sieved, weighed, and counted to obtain experimental data. The effectiveness of the fragment empirical model is verified by comparing the model calculation results with the experimental data. The proposed model can be used as a reference for civil blasting, protective engineering design, and explosion-damage assessment.

关键词： concrete structures explosion loads fragment behavior empirical model

Continuous variable quantum teleportation and remote state preparation between two space-separated local networks

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Science China(Information Sciences) 2024年第4期67卷 314-322页

作者： Siyu ren Dongmei HAN Meihong WANG Xiaolong SU State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-ElectronicsShanxi University Collaborative Innovation Center of Extreme Optics Shanxi University

Implementing quantum communication between space-separated local networks is essential for designing global quantum networks. In this study, we propose quantum teleportation and remote state preparation schemes between users of two space-separated local networks established by continuous-variable multipartite entangled states. In the proposed schemes, the quantum nodes belonging to the two distant local networks are first entangled by entanglement swapping, and then quantum communication protocols are realized. We show that quantum teleportation between any two users belonging to space-separated local networks can be realized with the assistance of other users, and squeezed thermal states can be remotely prepared in one local network by performing a homodyne projective measurement on the state in another distant local network. Our results provide a feasible approach for quantum communication between spaceseparated quantum networks with multipartite entangled states.

关键词： quantum communication quantum network quantum teleportation remote state preparation entanglement swapping continuous variable

Primitive functional groups directed distinct photocatalytic performance of imine-linked donor-acceptor covalent organic frameworks

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Nano Research 2024年第6期17卷 4994-5001页

作者： Xitong ren Jiajie Sun Yusen Li Feng Bai Key Laboratory for Special Functional Materials of Ministry of Education National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologySchool of Materials Science and Engineeringand Collaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004China School of Physics and Electronics Henan UniversityKaifeng 475004China

The combination of donor-acceptor(D-A)structures presents a viable strategy for fabricating covalent organic frameworks(COFs)with exceptional photocatalytic ***,the selection of functional groups on donor or acceptor building blocks and their effect on the macroscopic properties of COFs are *** this study,we tactfully synthesized a pair of Py-DBT-COFs from the same pyrene(Py)donor and 4,7-diphenylbenzo[c][1,2,5]thiadiazole(DBT)acceptor cores with distinct primitive functional *** primitive functional groups of building units determine the photocatalytic properties of corresponding ***,Py-C-DBT-COF synthesized from Py-4CHO and DBT-2NH_(2)showcases a splendid H_(2)evolution rate as high as 21,377.7μmol/(g·h)(with 5 wt.%Pt)originating from better charge transfer capacity,which is significantly superior to that of Py-N-DBT-COF constructed from Py-4NH_(2)and *** distinct photocatalytic performances of the two COFs are demonstrated to originate from the different charge separation and transfer *** work supplies a new avenue for optimizing the photocatalytic performance of D-A COFs from the perspective of primitive functional group selections.

关键词： covalent organic frameworks functional group donor-acceptor photocatalysis

Is Yang-Mills theory unitary in fractional spacetime dimensions?

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 59-64页

作者： Qingjun Jin Ke ren Gang Yang Rui Yu Graduate School of China Academy of Engineering Physics Beijing 100193China School of Physics and Astronomy Sun Yat-Sen UniversityZhuhai 519082China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Hangzhou 310024China School of Physical Science and Technology Inner Mongolia UniversityHohhot 010021China Beijing Computational Science Research Center Beijing 100193China

We present concrete evidence that Yang-Mills theory exhibits non-unitarity in non-integer spacetime *** violation of unitarity stems from evanescent operators that,while vanishing in four dimensions,are non-zero in general d *** demonstrate that these evanescent operators lead to the emergence of both negative-norm states and complex anomalous dimensions.

关键词： gauge field theories field theories in dimensions other than four renormalization

Path signature-based XAI-enabled network time series classification

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Science China(Information Sciences) 2024年第7期67卷 91-106页

作者： Le SUN Yueyuan WANG Yongjun ren Feng XIA Department of Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET) Nanjing University of Information Science and Technology School of Computing Technologies Royal Melbourne Institute of Technology

Classifying network time series(NTS) is crucial for automating network administration and ensuring cyberspace security. It enables the detection of anomalies, the identification of network attacks,and the monitoring of performance issues, thereby providing valuable support for network protection and optimization. However, modern communication networks pose challenges for NTS classification *** include handling large-scale and complex NTS data, extracting features from intricate datasets, and addressing explainability requirements. These challenges are particularly pronounced for complex 5G networks. Notably, explainability has become crucial for the widespread deployment of network automation for 5G networks and beyond. To tackle these challenges, we propose a path-signature-based NTS classification model called recurrent signature(Recur Sig). This innovative model is designed to overcome the time-consuming feature selection problem by utilizing deep-learning(DL) techniques. Additionally, it provides a solution for addressing the black-box issue associated with DL models in network automation systems(NAS) by incorporating an explainable classification approach. Extensive experimentation on various public datasets demonstrates that Recur Sig outperforms existing models in accuracy and explainability. The results indicate its potential for application in cyberspace security and automated network management, offering an explainable solution for network protection and optimization.

关键词： network time series classification explainable artificial intelligence path signature automated network management recurrent neural network

Parameter-Free Shifted Laplacian Reconstruction for Multiple Kernel Clustering

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1072-1074页

作者： Xi Wu Zhenwen ren F.Richard Yu the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010China the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010 the Guangxi Key Laboratory of Machine Vision and Intelligent Control Wuzhou UniversityWuzhou 543002 the Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ) Shenzhen 518060China

Dear Editor,This letter proposes a parameter-free multiple kernel clustering(MKC)method by using shifted Laplacian *** MKC can effectively cluster nonlinear data,but it faces two main challenges:1)As an unsupervised method,it is up against parameter problems which makes the parameters intractable to tune and is unfeasible in real-life applications;2)Only considers the clustering information,but ignores the interference of noise within Laplacian.

关键词： parameter letter Parameter