基于S-R和分解定理的二维几何非线性问题的虚单元法求解

应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝试使用一阶虚单元求解基于S-R和分解定理的二维几何非线性问题,以克服网格畸变的影响。基于重新定义的多项式位移空间基函数,推演获得一阶虚单元分析线弹性力学问题时允许位移空间向多项式位移空间的投影表达式;按照虚单元法双线性格式的计算规则,分析处理基于更新拖带坐标法和势能率原理的增量变分方程;进而建立离散系统方程及其矩阵表达形式,并编制MATLAB求解程序;采用常规多边形网格和畸变网格,应用该文算法分析均布荷载下的悬臂梁和均匀内压下的厚壁圆筒变形。结果与已有文献和ANSYS软件的对比表明:该文算法在两种网格中均可有效执行且具备足够数值精度。总体该文算法为基于S-R和分解定理的二维几何非线性问题求解提供了一种鲁棒方法。

电力物联网用户侧负荷数据动态R-树匹配方法

电力物联网用户侧负荷数据维度较大,导致数据匹配延时时间过长,为了解决上述问题,基于动态R-树实现电力物联网用户侧负荷数据动态匹配。建立负荷计算模型,分析负荷历史运行信息,实现数据检测。通过归一化函数完成归一化处理,提取动态特征,构建动态R-树,确定匹配机制,根据矩阵计算函数完成压缩处理,利用动态匹配算法更新集对R-树内部结构进一步加以修改,在清除矩形之前,利用叶结点的Hash索引得到R-树匹配矩阵,使用Hash搜索准确地找到目标矩形,增强分布与交互仿真中的实时性,实现用户侧负荷数据动态匹配。实验结果表明,研究的动态R-树匹配方法在数据插入、数据匹配、数据维护过程中的延时时间低于48ms,实时性较好。

危标R值法失效的情况及解决办法研究

论文根据某三层砖墙木屋盖的混合结构的鉴定评判,提出了多个基于JGJ 125-2016《危险房屋鉴定标准》中R值法的房屋鉴定评判失效的情况,这类情况计算的R值较小,最终房屋危险性评定为B级。然而这类情况的房屋状况较危险,实际房屋危险性更接近C级的释义。论文提出了将危标中的房屋危险性等级B级分成B1和B2两类的解决方法。经验证,该方法解决了被评判为B级但房屋实际状况较为危险的评判失效情况。

手动膜片钳检测盐酸罗哌卡因及其右旋异构体对HEK293细胞hERG电流的影响

目的研究比较盐酸罗哌卡因和盐酸罗哌卡因右旋异构体对高表达hERG钾通道的HEK293细胞hERG电流的影响。方法用手动膜片钳检测转染后hERG钾通道稳定表达的HEK293细胞电流,多菲莱德做阳性药,将盐酸罗哌卡因和盐酸罗哌卡因右旋异构体依次稀释成30.00、10.00、3.33、1.11、0.37μmol·L^(-1),依次作用于细胞,记录电流变化,计算抑制率。结果盐酸罗哌卡因0.37、1.11、3.33、10、30μmol·L^(-1)对电流Iherg-tail的抑制率分别为(6.12±0.30)%、(13.04±1.20)%、(19.21±0.33)%、(35.56±0.66)%、(65.37±4.17)%,IC_(50)为19.482μmol·L^(-1)(n=15)。盐酸罗哌卡因右旋异构体0.37、1.11、3.33、10.00、30.00μmol·L^(-1)对电流Iherg-tail的抑制率分别为(4.13±3.43)%、(7.34±5.60)%、(9.49±2.75)%、(16.60±0.87)%、(31.36±1.45)%,IC_(50)>30μmol·L^(-1)(n=15)。阳性对照药品多菲莱德0.00185、0.00556、0.01667、0.05000、0.15000μmol·L^(-1)对电流Iherg-tail的抑制率分别为(7.81±2.77)%、(19.67±1.88)%、(57.16±4.39)%、(89.71±3.55)%、(99.66±0.89)%、IC_(50)为0.015μmol·L^(-1)(n=15)。结论和阳性对照药品多菲莱德比较,盐酸罗哌卡因对hERG通道为弱抑制作用,盐酸罗哌卡因右旋异构体对hERG通道为无明显抑制作用。

基于LTE-R网络的高速铁路机车通信信息集成方法

现有的针对高速铁路机车通信的信息集成方法效果并不理想,为此,文章提出基于铁路长期演进(Long Term Evolution for Railway,LTE-R)网络的高速铁路机车通信信息集成方法。基于LTE-R技术构建高速铁路机车通信信息集成模型,结合LTE-R网络算法提取高速铁路机车通信信息,采用Revit软件和收集器收集数据,实现高速铁路机车通信信息的统计与集成。实验结果证明,文章设计的基于LTE-R网络的高速铁路机车通信信息集成方法,对高速铁路机车通信信息集成的自动化程度较高,可节省99.99%的时间,具有较好的应用性能。

基于NAR神经网络和R/S分析法的隧道围岩变形预测分析

为研究隧道围岩变形非线性特点,采用NAR神经网络和R/S分析法,对隧道围岩变形量和变形趋势进行分析。通过NAR神经网络对变形监测样本进行误差分析,认为NAR神经网络对围岩变形短期预测时的误差小精度高。运用R/S分析法对各变形时间序列进行重标极差分析,获得各时序的Hurst指数,分析其与围岩变形趋势的关系,并通过Hurst指数对隧道围岩变形趋势进行判定。结果表明:算例中的断面围岩变形仍然会呈增长趋势,但增长幅度在减小,且水平收敛的趋势性强于拱顶沉降,说明前者受随机扰动影响较小,后期稳定性相对更高。通过运用R/S分析法进行时间序列分析,不仅为围岩变形趋势预判提供了Hurst指数判据,同时也为围岩稳定性分析及治理提供了一种依据。

基于改进Faster R-CNN模型的水果分类识别

目的:提高水果类别识别准确率。方法:基于改进Faster R-CNN模型建立水果识别方法。使用正则化方法对高维参数进行权重衰减,以有效解决训练过程中可能出现的过拟合问题;在Faster R-CNN框架中添加两个损失函数:一个似然函数和一个正则化函数,以优化卷积层和池化层;以最小二乘法求解水果识别的目标函数;利用准确率、回召率、精度和F1分数对训练好的水果识别方法进行水果识别效果评估。结果:所提出的方法对水果识别的准确率、精度和回召率达到99.69%,0.9968,0.9948;与其他8种水果识别方法相比,所提出方法对水果识别的准确率、精度和回召率至少提高了0.91%,1.32%,0.51%。结论:该方法可准确识别水果种类。

基于改进Faster R-CNN和正交投影的无砟轨道板裂缝精细化测量

裂缝的检测和宽度识别是无砟轨道板养护维修作业的重要依据。为此,提出一种基于改进Faster R-CNN和正交投影的裂缝宽度测量方法,并基于虚拟模型合成数据,充分训练深度网络,实现对复杂背景下无砟轨道板表面裂缝的精准检测,以提高裂缝几何特征量化的可靠性。首先,基于二维CAD图纸建立参数化的无砟轨道结构三维BIM模型,并通过UE5物理引擎实现真实裂缝特征与虚拟轨道模型的随机融合和真实巡检场景渲染;然后,通过配置虚拟摄像机输出,模拟真实巡检场景下的虚拟裂缝图像,充分训练改进后的Faster R-CNN网络,并在轨道巡检车采集到的原始图像上进行测试;最后,采用正交投影法逐像素地计算检测结果中裂缝的宽度,并与人工取点测量结果进行对比分析。结果表明:改进后的Faster R-CNN网络对于裂缝检测的平均精度提高约10%;网络性能随训练数据的虚实图像比例而变化,于4∶1时达到饱和,平均精度达95.12%;使用融合裂缝数据集训练出的网络模型能够在保持高精准率的同时,达到更高的召回率,有效减少了裂缝的错检、漏检;与人工测量相比,正交投影法测得的裂缝最小宽度与最大宽度分别增大了3.64%和22.40%,测量结果更加稳定且接近真实值,具有更高的可靠性。

Fractal Method for Statistical Analysis Geological Data

This paper establishes the phase space in the light of spacial series data , discusses the fractal structure of geological data in terms of correlated functions and studies the chaos of these data . In addition , it introduces the R/S analysis for time series analysis into spacial series to calculate the structural fractal dimensions of ranges and standard deviation for spacial series data -and to establish the fractal dimension matrix and the procedures in plotting the fractal dimension anomaly diagram with vector distances of fractal dimension . At last , it has examples of its application .

Research on nonlinear R／S method and its application in earthquake prediction

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Reduced Differential Transform Method for Solving Nonlinear Biomathematics Models

In this paper,we study the approximate solutions for some of nonlinear Biomathematics models via the e-epidemic SI1I2R model characterizing the spread of viruses in a computer network and SIR childhood disease model.The reduced differential transforms method(RDTM)is one of the interesting methods for finding the approximate solutions for nonlinear problems.We apply the RDTM to discuss the analytic approximate solutions to the SI1I2R model for the spread of virus HCV-subtype and SIR childhood disease model.We discuss the numerical results at some special values of parameters in the approximate solutions.We use the computer software package such as Mathematical to find more iteration when calculating the approximate solutions.Graphical results and discussed quantitatively are presented to illustrate behavior of the obtained approximate solutions.

Preparation of Layered Potassium Titanate Whiskers with Large Length-diameter Ratio by KDC Method

Pure K2Ti4O9 whiskers were prepared by KDC（Kneading-Drying-Calcination） method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio（RT/K）, calcination temperature（TC） and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC（thermo gravimetric-differential scanning calorimeter）, XRD（X-ray diffraction）, and SEM（scanning electron microscope）. Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio（r）（over 250） can be obtained at RT/K = 2.9 and TC = 950 ℃.

On the Method of Multiplier-enlargement and Approximation of Unbounded Continuous Functions

By combining the classical appropriate functions “1, x, x 2” with the method of multiplier enlargement, this paper establishes a theorem to approximate any unbounded continuous functions with modified positive linear operators. As an example, Hermite Fejér interpolation polynomial operators are analysed and studied, and a general conclusion is obtained.

一个修正的非线性三项PRP共轭梯度算法

基于共轭梯度法迭代简单、计算高效的优势,提出一种修正三项PRP共轭梯度算法。该算法满足充分下降性,对非凸优化问题具有全局收敛性和R-线性收敛性。在无约束优化问题、马斯京根模型参数估计和图像复原问题的数值实验结果表明,该算法都具有更好性能。

Numerical stability of solution to delay differential equations under resolvent condition for Runge-Kutta methods

Deals with the application of Kreiss resolvent condition in the error growth analysis of numerical methods, and studies the stability of Runge Kutta method in respect of Kreiss resolvent condition with emphasis on the study on the subclass of collocation methods with abscissas in [0,1] by applying the methods to the test equation U′(t)=λU(t)+μU(t-τ)τ>0 with complex constraints μ and λ, and proves under some assumptions on the R K methods that the error growth is uniformly bounded in the stability region.

R/S method for evaluation of pollutant time series in environmental quality assessment

The significance of the fluctuation and randomness of the time series of each pollutant in environmental quality assessment is described for the first time in this paper. A comparative study was made of three different computing methods： the same starting point method, the striding averaging method, and the stagger phase averaging method. All of them can be used to calculate the Hurst index, which quantifies fluctuation and randomness. This study used real water quality data from Shazhu monitoring station on Taihu Lake in Wuxi, Jiangsu Province. The results show that, of the three methods, the stagger phase averaging method is best for calculating the Hurst index of a pollutant time series from the perspective of statistical regularity.

PVTxSTUDYOFBINARYSYSTEMR22／R152aWITHBURNETTMETHOD

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Estimating GARCH Modeling Using Metropolis-Hastings Method in R

This paper mainly talks about a popular approach of volatility of a GARCH-type model in R, while the disturbances are independent and have identical Student-t distribution. It uses the Metropolis-Hastings method to perform the computations and gives the programs in details in R.

几类r-冠图的星边染色

图的星边染色是指图G的一个正常边染色使得G中没有长为4的路或圈是2-边染色的.图G的星边色数是指图G有星边染色的最小颜色数.本文中研究路、圈、扇、轮的r-冠图的星边染色问题.使用图分解法,反证法,染色构造法,组合分析法等方法和理论,得到4类r-冠图的星边色数.

Projected Runge-Kutta methods for constrained Hamiltonian systems

Projected Runge-Kutta （R-K） methods for constrained Hamiltonian systems are proposed. Dynamic equations of the systems, which are index-3 differential-algebraic equations （DAEs） in the Heisenberg form, are established under the framework of Lagrangian multipliers. R-K methods combined with the technique of projections are then used to solve the DAEs. The basic idea of projections is to eliminate the constraint violations at the position, velocity, and acceleration levels, and to preserve the total energy of constrained Hamiltonian systems by correcting variables of the position, velocity, acceleration, and energy. Numerical results confirm the validity and show the high precision of the proposed method in preserving three levels of constraints and total energy compared with results reported in the literature.