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Fixed-Time Sliding Mode Control With Varying Exponent Coefficient for Modular Reconfigurable Flight Arrays

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 514-528页

作者： Jianquan Yang Chunxi Yang Xiufeng Zhang Jing na Faculty of Mechanical and Electrical Engineering Kunming University of Science and TechnologyKunming 650500 Yunnan International Joint Laboratory of Intelligent Control and Aoolication of Advanced Equipment Kunming 650500China IEEE

The modular system can change its physical structure by self-assembly and self-disassembly between modules to dynamically adapt to task and environmental requirements. Recognizing the adaptive capability of modular systems, we introduce a modular reconfigurable flight array(MRFA) to pursue a multifunction aircraft fitting for diverse tasks and requirements,and investigate the attitude control and the control allocation problem by using the modular reconfigurable flight array as a platform. First, considering the variable and irregular topological configuration of the modular array, a center-of-mass-independent flight array dynamics model is proposed to allow control allocation under over-actuated situations. Secondly, in order to meet the stable, fast and accurate attitude tracking performance of the MRFA, a fixed-time convergent sliding mode controller with state-dependent variable exponent coefficients is proposed to ensure fast convergence rate both away from and near the system equilibrium point without encountering the singularity. It is shown that the controller also has fixed-time convergent characteristics even in the presence of external disturbances. Finally,simulation results are provided to demonstrate the effectiveness of the proposed modeling and control strategies.

关键词： Control allocation dynamic model fixed-time stabilization modular reconfigurable flight array(MRFA) sliding mode

High-current pulsed electron beam modification on microstructure and performance of Cu/CuW diffusion bonding joints

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Rare Metals 2024年第6期43卷 2819-2831页

作者： na-na Tian Cong-Lin Zhang Peng Lyu Jin-Tong Guan Jie Cai Qing-Feng Guan Shun Guo School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China School of Material Science and Engineering Yancheng Institute of TechnologyYancheng 221051China Engineering Institute of Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang 212013China

This study investigates the influence of high-current pulsed electron beam(HCPEb)modification on the microstructure and shear strength of Cu/CuW *** solid-state diffusion bonding of modified-Cu(MCu)and modified-CuW(M-CuW)was achieved by HCPEb modification pretreatment at a temperature of 800-900℃and a pressure of 5 MPa for 10-50 *** demonstrate that HCPEb modification facilitates the dissolution of W and Cu,resulting in the formation of a Cu_(0.4)W_(0.6)solid solution and thus enhancing the uniform distribution of ***,HCPEb-induced defects play a beneficial role in promoting the diffusion process by providing fast diffusion paths for *** optimal joints with the maximum shear strength of 213.7 MPa were obtained through bonding M-Cu and M-CuW at 900℃and 5 MPa for 30 min,which attributes to the combined effects of fine-grained strengthening and solid solution ***,the application of HCPEb modification showcases its effectiveness in promoting element diffusion and enhancing the mechanical performance of the joints.

关键词： HCPEb Element diffusion Shear strength Crystal defects Surface modification

Dynamic Response Impact of Vehicle braking on Simply Supported beam bridges with Corrugated Steel Webs based on Vehicle-bridge Coupled Vibration Analysis

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 3467-3493页

作者： Yan Wang Siwen Li na Wei School of Civil Engineering Zhengzhou UniversityZhengzhou450001China

A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle *** modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this *** method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are *** results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the ***,the influence of wheelto-bridge friction forces is of particular significance and cannot be *** the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking *** favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by *** is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.

关键词： Corrugated steel web girder bridges simply supported beam bridges vehicle-bridge coupled vibration braking impact factor

A New Encrypted Traffic Identification Model based on VAE-LSTM-DRN

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Computers, Materials & Continua 2024年第1期78卷 569-588页

作者： Haizhen Wang Jinying Yan na Jia College of Computer and Control Engineering Qiqihar UniversityQiqihar161006China Heilongjiang Key Laboratory of big Data Network Security Detection and Analysis Qiqihar UniversityQiqiharChina

Encrypted traffic identification pertains to the precise acquisition and categorization of data from traffic datasets containing imbalanced and obscured *** extraction of encrypted traffic attributes and their subsequent identification presents a formidable *** existing models have predominantly relied on direct extraction of encrypted traffic data from imbalanced datasets,with the dataset’s imbalance significantly affecting the model’s *** the present study,a new model,referred to as UD-VLD(Unbalanced Dataset-VAE-LSTM-DRN),was proposed to address above *** proposed model is an encrypted traffic identification model for handling unbalanced *** encoder of the variational autoencoder(VAE)is combined with the decoder and Long-short term Memory(LSTM)in UD-VLD model to realize the data enhancement processing of the original unbalanced *** enhanced data is processed by transforming the deep residual network(DRN)to address neural network gradient-related ***,the data is classified and *** UD-VLD model integrates the related techniques of deep learning into the encrypted traffic recognition technique,thereby solving the processing problem for unbalanced *** UD-VLD model was tested using the publicly available Tor dataset and VPN *** UD-VLD model is evaluated against other comparative models in terms of accuracy,loss rate,precision,recall,F1-score,total time,and ROC *** results reveal that the UD-VLD model exhibits better performance in both binary and multi classification,being higher than other encrypted traffic recognition models that exist for unbalanced ***,the evaluation performance indicates that the UD-VLD model effectivelymitigates the impact of unbalanced data on traffic *** can serve as a novel solution for encrypted traffic identification.

关键词： Data enhancement LSTM deep residual network VAE

Survey on Fake Information Generation,Dissemination and Detection

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Chinese Journal of Electronics 2024年第3期33卷 573-583页

作者： Wanqiu CUI Dawei WANG na HAN School of national Security People's Public Security University of China big Data Center of The Ministry of Public Security

The current booming development of the Internet has put the public in an era of information overload,in which false information is mixed and spread *** phenomenon has seriously disturbed the social network ***,a substantial amount of research is beginning to be devoted to the effective management of fake *** analyze the abnormal characteristics of fake information from its mechanism of generation and *** view of different exceptional features,we systematically sort out and evaluate the existing studies on false content *** commonly used public datasets,metrics,and performance are categorized and compared,hoping to provide a basis and guidance for related *** study found that the current active social platforms show different *** future direction should point to mining platform features of multi-domain sources,multi-data forms,and multi-language heterogeneity to provide more valuable clues for fake information.

关键词： Fake information Abnormal characteristics Detection methods Public datasets

Molecular mechanism of flowering time regulation in brassica rapa:similarities and differences with Arabidopsis

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Horticultural Plant Journal 2024年第3期10卷 615-628页

作者： na Li Rui Yang Shuxing Shen Jianjun Zhao State Key Laboratory of North China Crop Improvement and Regulation Key Laboratory of Vegetable Germplasm Innovation and Utilization of HebeiCollaborative Innovation Center of Vegetable Industry in HebeiCollege of HorticultureHebei Agricultural UniversityBaodingHebei 071000China

Properly regulated flowering time is pivotal for successful plant *** floral transition from vegetative growth to reproductive growth is regulated by a complex gene regulatory network that integrates environmental signals and internal conditions to ensure that flowering takes place under favorable *** rapa is a diploid Cruciferae species that includes several varieties that are cultivated as vegetable or oil *** time is one of the most important agricultural traits of *** crops because of its influence on yield and *** transition to flowering in *** is regulated by several environmental and developmental cues,which are perceived by several signaling pathways,including the vernalization pathway,the autonomous pathway,the circadian clock,the thermosensory pathway,and gibberellin(GA)*** signals are integrated to control the expression of floral integrators brFTs and brSOC1s to regulate *** this review,we summarized current research advances on the molecular mechanisms that govern flowering time regulation in *** and compare this to what is known in Arabidopsis.

关键词： Flowering time brassica rapa Vernalization Photoperiod

Spatiotemporal characteristics of cultivated land use eco-efficiency and its influencing factors in China from 2000 to 2020

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Journal of Arid Land 2024年第3期16卷 396-414页

作者： LI Shaoting MU na REN Yanjun Thomas GLAUbEN College of Economics and Management Northwest A&F UniversityYangling 712100China Sino-German Center for Agricultural and Food Economics Northwest A&F UniversityYangling 712100China Leibniz Institute of Agricultural Development in Transition Economies(IAMO) Halle 06120Germany

Improving cultivated land use eco-efficiency(CLUE)can effectively promote agricultural sustainability,particularly in developing countries where CLUE is generally *** study used provincial-level data from China to evaluate the spatiotemporal evolution of CLUE from 2000 to 2020 and identified the influencing factors of CLUE by using a panel Tobit *** addition,given the undesirable outputs of agricultural production,we incorporated carbon emissions and nonpoint source pollution into the global benchmark-undesirable output-super efficiency-slacks-based measure(Gb-US-SbM)model,which combines global benchmark technology,undesirable output,super efficiency,and slacks-based *** results indicated that there was an upward trend in CLUE in China from 2000 to 2020,with an increase rate of 2.62%.The temporal evolution of CLUE in China could be classified into three distinct stages:a period of fluctuating decrease(2000-2007),a phase of gradual increase(2008-2014),and a period of rapid growth(2015-2020).The major grain-producing areas(MPAs)had a lower CLUE than their counterparts,namely,non-major grain-production areas(non-MPAs).The spatial agglomeration effect followed a northeast-southwest strip distribution;and the movement path of barycentre revealed a"P"shape,with Luoyang City,Henan Province,as the *** terms of influencing factors of CLUE,investment in science and technology played the most vital role in improving CLUE,while irrigation index had the most negative *** should be noted that these two influencing factors had different impacts on MPAs and ***,relevant departments should formulate policies to enhance the level of science and technology,improve irrigation condition,and promote sustainable utilization of cultivated land.

关键词： cultivated land use eco-efficiency(CLUE) slacks-based measure(SbM)model barycentre model standard deviation ellipse(SDE) panel Tobit model carbon emissions nonpoint source pollution

Reactive Transport Process of Earthquake-induced Hydrochemical Changes in Guanding Thermal Spring,Western Sichuan,China

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 241-249页

作者： na Jin JIANG Xue SHI Zheming CHEN Yanmei Hubei Key Laboratory of Petroleum Geochemistry and Environment(Yangtze University) Wuhan 430100China School of Environmental Studies China University of GeosciencesWuhan 430074China School of Water Resources and Environment China University of GeosciencesBeijing 100083China State Key Laboratory of Water Resource Protection and Utilization in Coal Mining Beijing 100000China

Earthquake-related hydrochemical changes in thermal springs have been widely observed;however,quantitative modeling of the reactive transport process is *** the present study,we apply reactive transport simulation to capture the hydrochemical responses in a thermal spring following the Wenchuan Ms 8.0 and Lushan Ms 7.0 *** first constrain deep reservoir geothermal fluid compositions and temperature by multicomponent geothermometry,and then a reactive geochemical transport model is constructed to reproduce the hydrochemical evolution *** results show that the recharge from the shallow aquifer increases gradually until it reaches a peak because of the permeability enhancement caused by the Lushan earthquake,which may be the mechanism to explain the earthquake-related hydrochemical *** contrast to the postseismic effect of the Wenchuan earthquake,the chemical evolution can be considered as hydrochemical anomalies related to the Lushan *** study proves that the efficient simulation of reactive transport processes is useful for investigating earthquake-related signals in hydrochemical time series.

关键词： earthquake hydrochemical changes reactive geochemical transport model Kangding area

Towards kernelizing the classifier for hyperbolic data

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Frontiers of Computer Science 2024年第1期18卷 17-31页

作者： Meimei YANG Qiao LIU Xinkai SUN na SHI Hui XUE School of Computer Science and Engineering Southeast UniversityNanjing 210096China MOE Key Laboratory of Computer Science and Information Integration(Southeast University) Nanjing 210096China

Data hierarchy,as a hidden property of data structure,exists in a wide range of machine learning applications.A common practice to classify such hierarchical data is first to encode the data in the Euclidean space,and then train a Euclidean ***,such a paradigm leads to a performance drop due to distortion of data embedding in the Euclidean *** relieve this issue,hyperbolic geometry is investigated as an alternative space to encode the hierarchical data for its higher ability to capture the hierarchical *** methods cannot explore the full potential of the hyperbolic geometry,in the sense that such methods define the hyperbolic operations in the tangent plane,causing the distortion of data *** this paper,we develop two novel kernel formulations in the hyperbolic space,with one being positive definite(PD)and another one being indefinite,to solve the classification tasks in hyperbolic *** PD one is defined via mapping the hyperbolic data to the Drury-Arveson(DA)space,which is a special reproducing kernel Hilbert space(RKHS).To further increase the discrimination of the classifier,an indefinite kernel is further defined in the Krein ***,we design a 2-layer nested indefinite kernel which first maps hyperbolic data into the DA spaces,followed by a mapping from the DA spaces to the Krein *** experiments on real-world datasets demonstrate the superiority ofthe proposed kernels.

关键词： data hierarchy hyperbolic cgeometry drury-arveson space krein space