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Sliced Average Variance Estimation for Tensor Data

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 630-655页

作者： Chuan-quan LI Pei-wen XIAO Chao YING Xiao-hui LIU school of Statistics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in finance and Economics Jiangxi University of Finance and EconomicsNanchang 330013China Biostatistics and Medical Informatics University of Wisconsin MadisonMadison 53726USA

Tensor data have been widely used in many fields,e.g.,modern biomedical imaging,chemometrics,and economics,but often suffer from some common issues as in high dimensional *** to find their low-dimensional latent structure has been of great interest for *** this end,we develop two efficient tensor sufficient dimension reduction methods based on the sliced average variance estimation(SAVE)to estimate the corresponding dimension reduction *** first one,entitled tensor sliced average variance estimation(TSAVE),works well when the response is discrete or takes finite values,but is not■consistent for continuous response;the second one,named bias-correction tensor sliced average variance estimation(CTSAVE),is a de-biased version of the TSAVE *** asymptotic properties of both methods are derived under mild *** and real data examples are also provided to show the superiority of the efficiency of the developed methods.

关键词： tensor data sliced average variance estimation sufficient dimension reduction central subspace

Modeling the Diffusion of New Energy Vehicles in China Considering Subsidy Policies

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Journal of Systems Science and Information 2024年第4期12卷 457-475页

作者： Lingling PEI Ruijin ZHAI Minghuan SHOU Jingzhong LUO school of Management Zhejiang University of Finance & Economics school of Management Hangzhou Dianzi University

The new energy vehicle(NEV) subsidy policy introduced in China in 2013 has significantly boosted the adoption and sales of NEVs, with sales increasing more than 40-fold. However, the mechanisms by which subsidy policies influence the diffusion of NEVs in China remain unclear, posing challenges for governments to design future strategies. Thus, the primary objective of this paper is to empirically examine the impact of subsidy policy on the diffusion of new energy vehicles and to forecast future development trends using the grey Bass model, a predictive model suited for new product adoption forecasting. Our findings suggest that while the sales of NEVs in China will continue to rise,the growth rate will slow. Key milestones include the first inflection points for new energy vehicles and battery electric vehicles, anticipated in 2025 and 2024 respectively, with peak sales expected in 2028 and 2027. These insights are crucial for manufacturers, enabling them to adjust their production strategies timely and enhance their resilience in the market.

关键词： grey predictive model grey Bass model subsidy policy new energy vehicle battery electric vehicle

Flow instability of supercritical hydrocarbon fuel in a multi-channel cooling system

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Chinese Journal of Aeronautics 2024年第2期37卷 283-295页

作者： Yichao JIN Kun WU Xuejun FAN institute of Applied Physics and Computational mathematics Beijing 100094China institute of Mechanics Chinese Academy of SciencesBeijing 100190China school of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Thermally-induced flow instabilities are a critical issue in multi-channel regenerative cooling *** particular,the interactions between Density-Wave Oscillations(DWO)and Flow Maldistribution(FMD)can result in complex and disastrous instability *** study investigates the instability behaviors of hydrocarbon fluid in a four-channel system with a constant heat flux ratio using both frequency-and time-domain *** the heat flux increases,the in-tube flow sequentially destabilizes in each channel and converges to new equilibrium states,leading to the emergence of FMD *** also causes the system eigenvalue to change repeatedly from negative to positive rather than increasing ***,the system eigenvalues are between those of the two most unstable channels,indicating that the stability behavior of the entire system is dictated by the most unstable *** FMD occurs,flow oscillations are activated in channels with weak stability,and the in-tube flow is observed to evolve into various flow patterns,including stable flow,self-sustained oscillation,oscillation divergence,quasiperiodic oscillation,and oscillation *** novel instability mode of oscillation excursion involves a spontaneous transition of operating *** oscillates from an equilibrium state and then stabilizes at a new operational state after oscillation-induced ***,the newfound stable state may also be only temporary,with the in-tube flow regressing to the initial state,resulting in quasi-periodic oscillation.

关键词： Cooling Supercritical fluids Hydrocarbons Flow instability Flow maldistribution Density-wave oscillations

Reliability of a Multicomponent Stress-strength Model Based on a Bivariate Kumaraswamy Distribution with Censored Data

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 478-507页

作者： Cong-hua CHENG school of mathematics and Statistics Zhaoqing UniversityZhaoqing 526061China

In this paper,we consider a system which has k statistically independent and identically distributed strength components and each component is constructed by a pair of statistically dependent elements with doubly type-II censored *** elements(X1,Y1),(X2,Y2),…,(Xk,Yk)follow a bivariate Kumaraswamy distribution and each element is exposed to a common random stress T which follows a Kumaraswamy *** system is regarded as operating only if at least s out of k(1≤s≤k)strength variables exceed the random *** multicomponent reliability of the system is given by Rs,k=P(at least s of the(Z1,…,Zk)exceed T)where Zi=min(Xi,Yi),i=1,…,*** Bayes estimates of Rs,k have been developed by using the Markov Chain Monte Carlo methods due to the lack of explicit *** uniformly minimum variance unbiased and exact Bayes estimates of Rs,k are obtained analytically when the common second shape parameter is *** asymptotic confidence interval and the highest probability density credible interval are constructed for Rs,*** reliability estimators are compared by using the estimated risks through Monte Carlo simulations.

关键词： stress-strength model bivariate Kumaraswamy distribution multicomponent reliability doubly Type-II censored scheme interval estimation

Characteristic Study of Self-Powered Sensors Based on Native Protein Composite Film

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Energy & Environmental Materials 2024年第1期7卷 226-232页

作者： Jiehui Xue Huijing Xiang Yanrong Zhang Jun Yang Xia Cao Zhonglin Wang Beijing institute of Nanoenergy and Nanosystems Chinese Academy of Sciences school of Resources Environment and Materials School of Physics Science and Technology Center on Nanoenergy Research Guangxi University Center for Green Innovation School of Mathematics and Physics University of Science and Technology Beijing Research Centre of Information Technology Shenzhen Institute of Information Technology school of Chemistry and Biological Engineering University of Science and Technology Beijing school of Materials Science and Engineering Georgia Institute of Technology

Flexible electronic sensors composed of flexible film and conductive materials play an increasingly important role in wearable and internet information *** has received more and more attention and made some progress over the ***,it is still a great challenge to prepare biocompatible and highly transparent conductive *** white is a pure natural protein-rich material.

关键词： flexible sensors intelligent sensing natural protein-rich material triboelectric nanogenerators

CONVERGENCE ANALYSIS OF SOME FINITE ELEMENT PARALLEL ALGORITHMS FOR THE STATIONARY INCOMPRESSIBLE MHD EQUATIONS

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Journal of Computational mathematics 2024年第1期42卷 49-70页

作者： Xiaojing Dong Yinnian He Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Laboratory of Intelligent Computing&Information Processing of Ministry of EducationSchool of Mathematics and Computational ScienceXiangtan UniversityXiangtan 411105China institute of Applied Physics and Computational mathematics Beijing 100088China school of mathematics and Statistics Xi'an Jiaotong UniversityXi'an 710049China

By combination of iteration methods with the partition of unity method(PUM),some finite element parallel algorithms for the stationary incompressible magnetohydrodynamics(MHD)with different physical parameters are presented and *** algorithms are highly *** first,a global solution is obtained on a coarse grid for all approaches by one of the iteration *** parallelized residual schemes,local corrected solutions are calculated on finer meshes with overlapping *** subdomains can be achieved flexibly by a class of *** proposed algorithm is proved to be uniformly stable and ***,one numerical example is presented to confirm the theoretical findings.

关键词： Partition of unity method Local and parallel algorithm Finite element method Iteration methods Magnetohydrodynamics

Fourier Transform of Anisotropic Hardy Spaces Associated with Ball Quasi-Banach Function Spaces and Its Applications to Hardy-Littlewood Inequalities

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Acta Mathematicae Applicatae Sinica 2024年

作者： Chao-an LI Xian-jie YAN Da-chun YANG Laboratory of mathematics and Complex Systems (Ministry of Education of China) School of Mathematical Sciences Beijing Normal University institute of Contemporary mathematics School of Mathematics and Statistics Henan University

Let A be a general expansive matrix and X be a ball quasi-Banach function space on ■~n, whose certain power（namely its convexification） supports a Fefferman-Stein vector-valued maximal inequality and the associate space of whose other power supports the boundedness of the powered Hardy-Littlewood maximal *** HXA（■~n） be the anisotropic Hardy space associated with A and *** authors first prove that the Fourier transform of f ∈ HXA（■~n） coincides with a continuous function F on ■~n in the sense of tempered ***,the authors obtain a pointwise inequality that the function F is less than the product of the anisotropic Hardy space norm of f and a step function with respect to the transpose matrix of the expansive matrix *** this,the authors further induce a higher order convergence for the function F at the origin and give a variant of the Hardy-Littlewood inequality in HXA（■~n）.All these results have a wide range of ***,the authors apply these results,respectively,to classical（variable and mixed-norm）Lebesgue spaces,Lorentz spaces,Orlicz spaces,Orlicz-slice spaces,and local generalized Herz spaces and,even on the last four function spaces,the obtained results are completely new.

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Digital signal acquisition system for complex nuclear reaction experiments

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Nuclear Science and Techniques 2024年第1期35卷 124-133页

作者： Wei-Liang Pu Yan-Lin Ye Jian-Ling Lou Jia-Hao Chen school of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China institute of Applied Physics and Computational mathematics Beijing 100094China

A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control *** proposed digital system can be combined with a conventional analog data acquisition system to provide more *** performance of the combined system was veri-fied using experimental data.

关键词： Digital signal acquisition system Trigger Programmable logic Timestamp

Dynamics of a predator-prey system with sublethal effects of pesticides on pests and natural enemies

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International Journal of Biomathematics 2024年第1期17卷 151-175页

作者： Xiangjun Dai Jianjun Jiao Qi Quan Airen Zhou school of Mathematical Sciences Guizhou Normal University Guiyang 550025P.R.China school of mathematics and Statistics Guizhou University of finance and Economics Guiyang 550025 P.R.China school of Date Science Tongren University Tongren 554300P.R.China

Considering the influence of sublethal concentration of pesticides on pests and natural enemies,we propose a pest-management model with impulsive effect on chemical control and biological control strategies periodic spraying pesticide and releasing predatory natural *** using the Floquet theory and the comparison theorem of impulsive differential equations,a sufficient condition for the global asymptotic stability of the pest-eradication periodic solution is *** persistence of the system is further studied,and a sufficient condition for the persistence of the system is ***,some numerical simulations are shown to verify our theoretical *** works indicate that the sublethal effects of insecticides and the release of predatory natural enemies play significant roles in pest control in agricultural production.

关键词： Predator-prey system sublethal effect global asymptotic stability permanence