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Mathematical modeling of female breast cancer in Japan

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International Journal of Biomathematics 2020年第4期13卷 33-47页

作者： Ahmed Nagah Asmaa Amer xinan zhang School of Mathematics and Statistics Central China Normal UniversityWuhan 430079P.R.China Mathematics Department Faculty of Science Zagazig UniversityZagazigEgypt Mathematics Department Faculty of Science Menoufia UniversityEgypt

Cancer incidence rates are significantly diferent all over the *** cancer is affected by many factors,the most important being genetics and *** aim of this paper is to study the mutation mechanisms of breast cancer for Japanese women by fitting the incidence data of three high-quality population areas in Japan from 1985 to *** achieve this goal,we have set up multi-stage models within the mathematical model of Moolgavkar,Venzon,and *** models take both mutation rates and clonal expansion rates as parameters in each compartment into *** on our simulation outcomes,two to twelve driver mutations are sufficient in the pathway to female breast cancer in *** the other hand,a previous study demonstrated that breast cancer in American women requires two to fourteen gene mutations to get a cancerous ***,the 3-stage mat hematical model is the optimal model as it fits clinical data very nicely for all affected cases of females in Japan and the *** genetic instability has a promincnt effect on the tumorigenesis of Japanese females caused by the first four driver *** calculated results for Japanese women are compared with previous works for American women.

关键词： Breast cancer multi-stage models genetic instability chi-square test

DTFLOW:Inference and Visualization of Single-cell Pseudotime Trajectory Using Diffusion Propagation

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Genomics, Proteomics & Bioinformatics 2021年第2期19卷 306-318页

作者： Jiangyong Wei Tianshou Zhou xinan zhang Tianhai Tian College of Science Huazhong Agricultural UniversityWuhan 430070China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073China School of Mathematics and Statistics Sun Yat-sen UniversityGuangzhou 510275China School of Mathematics and Statistics Central China Normal UniversityWuhan 430079China School of Mathematics Monash UniversityMelbourneVIC 3800Australia

One of the major challenges in single-cell data analysis is the determination of cellular developmental trajectories using single-cell *** substantial studies have been conducted in recent years,more effective methods are still strongly needed to infer the developmental processes *** work devises a new method,named DTFLOW,for determining the pseudotemporal trajectories with multiple *** consists of two major steps:a new method called Bhattacharyya kernel feature decomposition(BKFD)to reduce the data dimensions,and a novel approach named Reverse Searching on k-nearest neighbor graph(RSKG)to identify the multi-branching processes of cellular *** BKFD,we first establish a stationary distribution for each cell to represent the transition of cellular developmental states based on the random walk with restart algorithm,and then propose a new distance metric for calculating pseudotime of single cells by introducing the Bhattacharyya kernel *** effectiveness of DTFLOW is rigorously examined by using four single-cell *** compare the efficiency of DTFLOW with the published state-of-the-art *** results suggest that DTFLOW has superior accuracy and strong robustness properties for constructing pseudotime *** Python source code of DTFLOW can be freely accessed at https://***/statway/DTFLOW.

关键词： Single-cell heterogeneity Pseudotime trajectory Manifold learning Bhattacharyya kernel

Global dynamics and optimal control of an influenza model with vaccination, media coverage and treatment

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International Journal of Biomathematics 2017年第5期10卷 159-183页

作者： Lianwen Wang Zhijun Liu Dashun Xu xinan zhang School of Mathematics and Statistics Central China Normal University 430079 Wuhan P. R. China Department of Mathematics Hubei University for Nationalities 445000 Enshi Hubei P. R. China Department of Mathematics Southern Illinois University Carbondale IL 62901 USA School of Mathematics and Statistics Central China Normal University 530079 Wuhan P. R. China

In this work, in order to identify the most effective measure and combinations of several measures to control influenza spread, we propose an SVEIAR influenza model with imperfect vaccination, media coverage and antiviral treatment. The global dynamics of the model is explored. Sensitivity analysis of the basic reproduction number and the endemic equilibrium is conducted to evaluate the effectiveness of influenza control measures. Purthermore, an optimal control problem incorporating the three measures is formulated to design optimal control strategies for influenza. The cost-effectiveness analysis reveals that combining the three measures is the most cost-effective among the strategies considered. Numerical simulations show that media propaganda can play a dominant role in curbing influenza transmission.

关键词： SVEIAR influenza model optimal control media coverage vaccination antiviral treatment.

Low-complexity model predictive control of a four-level active neutral point clamped inverter without weighting factors

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Transportation Safety and Environment 2024年第2期6卷 96-103页

作者： Chaoqun Xiang Ziyin Fan Songyang Jiang xinan zhang Shu Cheng School of Traffic and Transportation Engineering Central South UniversityChangsha 410075HunanChina CRRC Dalian Electric Traction R&D Center Co. LtdDalian 116200LiaoningChina School of Engineering The University of Western AustraliaPerthWA 6009Australia

The four-level active neutral point clamped(ANPC)inverter has become increasingly widely used in the renewable energy indus-try since it offers one more voltage level without increasing the total number of active switches compared to the three-level ANPC *** model predictive current control(MPCC)is a promising control method for multi-level ***,the conven-tional MPCC suffers from high computational complexity and tedious weighting factor tuning in multi-level inverter applications.A low-complexity MPCC without weighting factors for a four-level ANPC inverter is proposed in this *** computational burden and voltage vector candidate set are reduced according to the relationship between voltage vector and neutral point voltage *** proposed MPCC shows excellent steady-state and dynamics performances while ensuring the neutral point voltage *** efficacy of the proposed MPCC is verified by simulation and experimental results.

关键词： four-level active neutral point clamped(ANPC)inverter model predictive current control(MPCC) low complexity without weighting factors

电容电压平衡的四电平有源中性点钳位逆变器的改进模型预测电流控制

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电工技术学报 2024年第18期39卷 5826-5838页

作者：向超群杜京润 zhang xinan 席振丁颢中南大学交通运输工程学院长沙410075 西澳大学电气电子与计算机工程学院克劳利WA6009

多电平有源中点钳位(ANPC)逆变器具有功率器件电压应力小、电流谐波低和器件损耗可调控等优点,被广泛应用于工业驱动中。针对四电平ANPC(4L-ANPC)逆变器的控制与调制研究相对较少,现有的调制方案实现复杂,中点电压(NPV)控制难度较大。因... 详细信息

多电平有源中点钳位(ANPC)逆变器具有功率器件电压应力小、电流谐波低和器件损耗可调控等优点,被广泛应用于工业驱动中。针对四电平ANPC(4L-ANPC)逆变器的控制与调制研究相对较少,现有的调制方案实现复杂,中点电压(NPV)控制难度较大。因此,该文针对三相4L-ANPC逆变器,提出一种改进的有限集模型预测电流控制(FS-MPCC)算法,避免了复杂的调制过程。首先,使用仅包含电流误差的代价函数对位于六边形顶点的6个大电压矢量进行寻优;其次,对参与第一步寻优的大矢量划分扇区,使用包含电流误差和电容电压误差的代价函数对最优大矢量所在扇区的所有电压矢量滚动寻优,得到目标电压矢量并作用于逆变器;最后,仿真和实验结果表明,与传统的FS-MPCC相比,所提方法在降低系统计算负担的同时,还具有较好的控制性能和电容电压平衡能力。

关键词：四电平有源中点钳位逆变器有限集模型预测电流控制电容电压平衡代价函数

MATHEMATICAL MODELING AND BIFURCATION ANALYSIS FOR A BIOLOGICAL MECHANISM OF CANCER DRUG RESISTANCE

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Acta Mathematica Scientia 2024年第3期44卷 1165-1188页

作者：包康博梁桂珍田天海张兴安 School of Information Engineering and Artificial Intelligence Lanzhou University of Finance and EconomicsLanzhou730020China School of Mathematics and Statistics Central China Normal UniversityWuhan430079China School of Mathematics and Information Science Xinxiang UniversityXinxiang453003China School of Mathematical Sciences Monash UniversityMelbourneVIC3800Australia

Drug resistance is one of the most intractable issues in targeted therapy for cancer *** has also been demonstrated to be related to cancer heterogeneity,which promotes the emergence of treatment-refractory cancer cell *** on how cancer cells develop resistance during the encounter with targeted drugs and the immune system,we propose a mathematical model for studying the dynamics of drug resistance in a conjoint heterogeneous tumor-immune *** analyze the local geometric properties of the equilibria of the *** simulations show that the selectively targeted removal of sensitive cancer cells may cause the initially heterogeneous population to become a more resistant ***,the decline of immune recruitment is a stronger determinant of cancer escape from immune surveillance or targeted therapy than the decay in immune predation *** analysis of model parameters provides insight into the roles of the immune system combined with targeted therapy in determining treatment outcomes.

关键词： mathematical model drug resistance cancer heterogeneity immune system targeted therapy

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基于符号距离场的多体系统碰撞动力学研究

力学学报 2024年第9期56卷 2703-2712页

作者：张西南游浦刘铸永上海交通大学船舶海洋与建筑工程学院水动力学教育部重点实验室上海200240

多体系统动力学中的接触碰撞问题是典型的边界非线性问题,对其动力学仿真面临着巨大的数值困难.由于求解过程中需要一直进行复杂的接触碰撞检测,严重地影响了数值计算效率.为了实现对多体系统动力学中接触碰撞问题的快速求解,文章提出... 详细信息

多体系统动力学中的接触碰撞问题是典型的边界非线性问题,对其动力学仿真面临着巨大的数值困难.由于求解过程中需要一直进行复杂的接触碰撞检测,严重地影响了数值计算效率.为了实现对多体系统动力学中接触碰撞问题的快速求解,文章提出一种改进的基于符号距离场的多体系统动力学接触碰撞检测算法.通过对预先生成的符号距离场进行三线性插值,求解出空间中任意一点距离物体表面的最短距离和法向量.将接触碰撞检测分为全局检测和局部检测两个过程,首先在全局检测时利用OBB包围盒技术对物体之间是否存在潜在接触可能性进行快速判断;然后在局部检测时基于符号距离场信息并结合八叉树结构对接触碰撞检测算法进行优化.分别采用Hertz接触力模型和基于速度的库伦摩擦力模型,建立了多刚体系统非连续动力学方程.最后,通过对典型的算例和空间站交会对接的工程案例进行仿真,验证了所提方法在解决复杂多体系统碰撞动力学问题时的正确性和高效性.该方法可以进一步拓展到复杂构型刚体与柔性体的接触碰撞动力学研究.

关键词：符号距离场碰撞检测多体系统八叉树交会对接

FIVE LIMIT CYCLES TO A CLASS OF SYSTEMS IN R^3

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Annals of Differential Equations 2011年第2期27卷 190-195页

作者： Lianhua Ma, Cuihong Yang , xinan zhang (School of Math. and Statistics, Central China Normal University, Wuhan 430079)

In this paper, a bridge between near-homogeneous and homogeneous vector fields in R 3 is found. By the relationship between homogeneous vector fields and the induced tangent vector fields of two-dimensional manifold S 2 , we prove the existence of at least 5 isolated closed orbits for a class of n + 1 (n ≥ 2) systems in R 3 , which are located on the five invariant closed cones of the system.

关键词： limit cycle invariant cone vector field

The Research on Violations and Countermeasures to Accounting Information Disclosure of the Listed Companies in China

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The Research on Violations and Countermeasures to Accounting...