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A Note on P m-Factorizable Topological Groups

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Journal of Mathematical Research with Applications 2024年第2期44卷 209-212页

作者： Chunjie MA Liangxue PENG Beijing University of Technology School of mathematics department of mathematics statistics and Mechanics

In this paper, we define a new class of P m-factorizable topological groups. A topological group G is called P m-factorizable if, for every continuous function f : G → M to a metrizable space M, one can find a perfect homomorphism π : G → K onto a second-countable topological group K and a continuous function g : K → M such that f = g■π. We show that a topological group G is P m-factorizable if and only if it is P R-factorizable. And we get that if G is a P m-factorizable topological group and K is any compact topological group, then the group G × K is P m-factorizable.

关键词： R-factorizable PR-factorizable m-factorizable Pm-factorizable M-factorizable

Dynamics and synchronization of neural models with memristive membranes under energy coupling

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Chinese Physics B 2024年第5期33卷 316-322页

作者：万婧玥吴富强马军汪文帅 School of mathematics and statistics Ningxia UniversityYinchuan 750021China Ningxia Basic Science Research Center of mathematics Ningxia UniversityYinchuan 750021China department of Physics Lanzhou University of TechnologyLanzhou 730050China

Dynamical modeling of neural systems plays an important role in explaining and predicting some features of biophysical *** electrophysiological environment inside and outside of the nerve cell is *** to the continuous and periodical properties of electromagnetic fields in the cell during its operation,electronic components involving two capacitors and a memristor are effective in mimicking these physical *** this paper,a neural circuit is reconstructed by two capacitors connected by a memristor with periodical *** is found that the memristive neural circuit can present abundant firing patterns without *** Hamilton energy function is deduced using the Helmholtz ***,a neuronal network consisting of memristive neurons is proposed by introducing energy *** controllability and flexibility of parameters give the model the ability to describe the dynamics and synchronization behavior of the system.

关键词： memristor neuronal model energy synchronization

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A Simulation-Extrapolation Approach to the Analysis of Interval-Censored Failure Time Data with Mis-Measured Covariates

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Journal of Systems Science & Complexity 2024年

作者： FENG Fan ZHAO Shishun LI Shuwei SUN Jianguo School of Economics and statistics Guangzhou University School of mathematics Jilin University School of mathematics Jilin University department of statistics University of Missouri

Interval-censored failure time data arise frequently in periodical follow-up studies including clinical trials and epidemiological surveys. In addition, some covariates may be subject to measurement errors due to the instrumental contamination, biological variation or other reasons. For the analysis of interval-censored data with mis-measured covariates, the existing methods either assume a parametric model or rely on the availability of replicated surrogate measurements for the error-prone covariate, which both have obvious limitations. To overcome these shortcomings, the authors propose a simulation-extrapolation estimation procedure under a general class of transformation models. The resulting estimators are shown to be consistent and asymptotically normal. The numerical results obtained from a simulation study indicate that the proposed method performs reasonably well in *** particular, the proposed method can reduce the estimation bias given by the naive method that does not take measurement errors into account. Finally, the proposed method is applied to a real data set on hypobaric decompression sickness.

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Testing high-dimensional covariance structures using double-normalized observations Dedicated to the Memory of Professor Xiru Chen on the Twentieth Anniversary of His Passing

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Science China mathematics 2024年

作者： Yanqing Yin Huiqin Li Zhidong Bai School of mathematics and statistics Chongqing University School of mathematics and statistics Northeast Normal University

In this paper, we focus on the test for high-dimensional covariance structures using doublenormalized observations for an elliptical population. By investigating the limiting spectral properties of the sample covariance matrix of double-normalized observations, we propose test statistics applicable for testing the diagonality of the population covariance matrix. Extensive simulations are conducted to investigate the performances of the proposed test in various situations.

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Modified DS np Chart Using Generalized Multiple Dependent State Sampling under Time Truncated Life Test

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2471-2495页

作者： Wimonmas Bamrungsetthapong Pramote Charongrattanasakul Division of Applied statistics Department of Mathematics and Computer ScienceFaculty of Science and TechnologyRajamangala University of Technology ThanyaburiPathum Thani12110Thailand Division of mathematics Department of Mathematics and Computer ScienceFaculty of Science and TechnologyRajamangala University of Technology KrungthepBangkok10120Thailand

This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of the product based on the time truncated life test employing theWeibull *** control chart developed supports the examination of the mean lifespan variation for a particular product in the process of *** control limit levels are used:the warning control limit,inner control limit,and outer control ***,they enhance the capability for variation detection.A genetic algorithm can be used for optimization during the in-control process,whereby the optimal parameters can be established for the proposed control *** control chart performance is assessed using the average run length,while the influence of the model parameters upon the control chart solution is assessed via sensitivity analysis based on an orthogonal experimental design withmultiple linear regression.A comparative study was conducted based on the out-of-control average run length,in which the developed control chart offered greater sensitivity in the detection of process shifts while making use of smaller samples on average than is the case for existing control ***,to exhibit the utility of the developed control chart,this paper presents its application using simulated data with parameters drawn from the real set of data.

关键词： Modified DS np chart generalizedmultiple dependent state sampling time truncated life test Weibull distribution average run length average sample size

Asymptotic Inference in the Random Coefficient Autoregressive Model with Time-functional Variance Noises

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 320-346页

作者： En-wen ZHU Zi-wei DENG Han-jun ZHANG Jun CAO Xiao-hui LIU department of mathematics and statistics Changsha University of Science and TechnologyChangsha 410114China School of mathematics and Computational Science Xiangtan UniversityXiangtan 411105China School of statistics and Data Science and Key Laboratory of Data Science in Finance and EconomicsJiangxi University of Finance and EconomicsNanchang 330013China

This paper considers the random coefficient autoregressive model with time-functional variance noises,hereafter the RCA-TFV *** first establish the consistency and asymptotic normality of the conditional least squares estimator for the constant *** semiparametric least squares estimator for the variance of the random coefficient and the nonparametric estimator for the variance function are constructed,and their asymptotic results are reported.A simulation study is presented along with an analysis of real data to assess the performance of our method in finite samples.

关键词： random coefficient autoregressive model time-functional variance conditional least squares semiparametric least squares

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A unified Minorization-Maximization approach for estimation of general mixture models

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Applied mathematics(A Journal of Chinese Universities) 2024年第2期39卷 343-362页

作者： HUANG Xi-fen LIU Deng-ge ZHOU Yun-peng ZHU Fei School of mathematics Yunnan Normal UniversityKunming 650092China department of statistics and Actuarial Science The University of Hong KongHong KongChina

The mixed distribution model is often used to extract information from heteroge-neous data and perform modeling *** the density function of mixed distribution is complicated or the variable dimension is high,it usually brings challenges to the parameter es-timation of the mixed distribution *** application of MM algorithm can avoid complex expectation calculations,and can also solve the problem of high-dimensional optimization by decomposing the objective *** this paper,MM algorithm is applied to the parameter estimation problem of mixed distribution *** method of assembly and decomposition is used to construct the substitute function with separable parameters,which avoids the problems of complex expectation calculations and the inversion of high-dimensional matrices.

关键词： MM algorithm mixed distribution model parameter estimation assembly decomposition tech-nology parameter separation

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Adaptive Sparse Grid Discontinuous Galerkin Method:Review and Software Implementation

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Communications on Applied mathematics and Computation 2024年第1期6卷 501-532页

作者： Juntao Huang Wei Guo Yingda Cheng department of mathematics and statistics Texas Tech UniversityLubbockTX79409USA department of Computational mathematics Science and EngineeringMichigan State UniversityEast LansingMI48824USA department of mathematics Michigan State UniversityEast LansingMI48824USA

This paper reviews the adaptive sparse grid discontinuous Galerkin(aSG-DG)method for computing high dimensional partial differential equations(PDEs)and its software *** C++software package called AdaM-DG,implementing the aSG-DG method,is available on GitHub at https://***/JuntaoHuang/*** package is capable of treating a large class of high dimensional linear and nonlinear *** review the essential components of the algorithm and the functionality of the software,including the multiwavelets used,assembling of bilinear operators,fast matrix-vector product for data with hierarchical *** further demonstrate the performance of the package by reporting the numerical error and the CPU cost for several benchmark tests,including linear transport equations,wave equations,and Hamilton-Jacobi(HJ)equations.

关键词： Adaptive sparse grid Discontinuous Galerkin High dimensional partial differential equation Software development

A Study on the Transmission Dynamics of the Omicron Variant of COVID-19 Using Nonlinear Mathematical Models

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2265-2287页

作者： S.Dickson S.Padmasekaran Pushpendra Kumar Kottakkaran Sooppy Nisar Hamidreza Marasi department of mathematics Periyar UniversitySalemTamilnadu636011India Faculty of Engineering and Natural Sciences Istanbul Okan UniversityIstanbulTurkey department of mathematics College of Science and Humanities in AlkharjPrince Sattam Bin Abdulaziz UniversityAlkharj11942Saudi Arabia department of Applied mathematics Faculty of MathematicsStatistics and Computer ScienceUniversity of TabrizTabrizIran

This research examines the transmission dynamics of the Omicron variant of COVID-19 using SEIQIcRVW and SQIRV models,considering the delay in converting susceptible individuals into infected *** significant delays eventually resulted in the pandemic’s *** ensure the safety of the host population,this concept integrates quarantine and the COVID-19 *** investigate the stability of the proposed *** fundamental reproduction number influences stability *** to our findings,asymptomatic cases considerably impact the prevalence of Omicron infection in the *** real data of the Omicron variant from Chennai,Tamil Nadu,India,is used to validate the outputs.

关键词： Omicron local stability reproduction number steady states global stability