基于偏最小二乘法的AMT离合器片表面温度预测

采用偏最小二乘回归方法,经交叉有效性检验建立了接合正压力的平均值、接合转速、滑摩时间与摩擦片表面最高温度的关系模型,模型对各种因变量的累计解释能力超过90%,通过该模型计算得到的拟合值与实际值的平均相对误差为3.90%,优于最小二乘支持向量机的预测效果,为AMT离合器开发、控制设计的优化及实现过温保护提供了依据.     

城市火灾次数与气象因素的Adaptive-Lasso分析

为研究城市火灾次数与气象因素的关系,以天津市的火灾数据为例,建立月度火灾次数与温度、风速、降雨量、日照、湿度等相关的各月气象因素及上月火灾起数间的线性回归模型.通过Adaptive-Lasso方法对上述变量进行选择并估计其参数,并对所得模型进行了分析比较,同时预测分析了2008年上半年火灾发生数.研究表明,通过Adaptive-Lasso方法建立的线性回归模型能够更好地预测火灾次数.     

苎麻纤维细度测试与分析的灰色模型

基于灰色系统理论的灰色建模应用于试验数据的相关分析 ,比基于数理统计的回归分析在实际应用中由于所需样本容量较小而具有明显的优点 ,特别对贫信息系统适用 .从而可避免在回归分析中因样本容量太小而致使回归方程的误差不可预测的弊端 .鉴于上述原理 ,本文采用灰色系统理论建立了苎麻纤维Tex数 Y与投影宽度 X之间的灰色 GM( 1 ,2 )模型 ,并进行了误差分析 .利用此模型探索了通过测定苎麻纤维投影宽度来计算其 Tex数的方法 .为生产工艺控制、产品质量检验和监督提供了一种简便而科学的办法 .     

钛合金插铣过程温度场的数学建模与有限元分析

从金属切削理论出发分析了钛合金插铣过程的切削热产生机理,推导出工件的热传导方程式,并在此基础上建立钛合金插铣的数学模型,应用Galerkin有限元方法对工件的热传导方程进行推导计算,随后利用Matlab进行数值模拟,最终得到工件稳定后温度分布图.通过数值计算结果与实验结果对比,验证了有限元模型具有可靠和高精度优点.对钛合金插铣过程加工参数的优化和刀具的设计提供了重要参考依据.     

基于数据包络分析的工程监理评标决策模型研究

以工程项目业主方视角基于数据包络分析的理论和方法建立了工程监理评标决策模型.首先,分析影响工程监理活动成效的因素,提取工程监理标原始评价指标,为消除原始指标间相关性带来的影响,采用主成分分析法建立工程监理标综合评价指标体系.其次,选取合适的输入和输出指标,建立工程监理评标决策的数据包络分析(DEA)模型.最后,通过实证分析,对该评标决策模型的操作性和有效性进行验证.为业主方提供了更为科学合理的评标决策方法,为规范建筑业市场运行秩序提供理论依据.     

基于误差传递的Vague值数据回归分析

Vague值数据是重要的符号数据,也是处理一类模糊问题的手段.基于误差传递的理论,提出了Vague值数据的回归分析方法.在分析原有Vague集相似性测度的基础上,提出了一种新的Vague集相似性测度,并以此来评价Vague值数据的回归模型.通过数值事例计算,验证了该回归模型的有效性.     

随机缺失函数型时间序列数据的k近邻回归估计

针对响应变量随机缺失的强混合函数型时间序列数据,首次提出了非参数回归模型的k近邻估计,并在一些正则条件下建立了k近邻回归算子的几乎完全一致收敛速度.此研究不仅推进了函数型非参数模型的理论研究,也为函数型数据的实际应用领域提供了理论支撑.     

大数据背景下分布式支持向量回归模型研究

为解决传统的支持向量回归模型在处理大规模数据时计算效率较低的局限,文章将交互有效方法与支持向量回归模型相结合,提出了基于交互有效方法的分布式支持向量回归模型(CE-SVR).该模型首先采用分布式存储方式将大规模数据随机分配给多台机器,其次采用交互有效方法构建支持向量回归的近似损失函数替代全局损失函数获得近似预测结果,能够有效地分析大规模数据.数值模拟和应用研究的结果表明:在线性模型中,文章所提出模型的预测性能与全局支持向量回归模型基本一致,且显著优于基于单轮型方法的分布式支持向量回归模型(OS-SVR);在非线性模型中,文章所提出模型的预测性能会随着机器数的增加而降低,但其预测性能显著优于OS-SVR模型.     

基于麻雀搜索算法和广义回归神经网络的玉米产量预测

针对新疆北部地区在玉米生产过程中存在的水肥利用率低下问题,提出一种基于麻雀搜索算法和广义回归神经网络模型的玉米产量预测方法,以探索水肥因素与玉米产量间的非线性关系,可为优化新疆北部地区春播玉米灌溉制度及水肥配饰方略提供理论指导.该方法采用36组既有玉米生产数据,通过广义回归神经网络技术建立模型,使用麻雀搜索算法对关键参数进行优化,降低了人为因素对模型超参数选择的影响.该模型用于新疆灌溉中心试验站的玉米产量预测仿真实验,证明该模型预测性能良好,相较于传统模型,在学习速度、预测精度及鲁棒性上具有优势,可有效预测新疆北部地区春播玉米产量.     

有限元法在船体总振动中的应用

当用梁理论计算船体振动的高谐调特性时,理论计算值与实际试验量测值有较大偏差.这样,梁理论不能作为计算高协调振动的一个实际可用的方法.本文应用二维和三维有限元模型计算船体垂直振动.采用我们自己编制的多单元结构动力分析程序DDJ(DL)在国产709计算机上计算了船体A和船体B两个船的船体总振动特性. 计算结果与实测结果比较表明,建立的二维有限元模型较之传统梁模型有明显的优越性.理论计算与实测之间的偏差大大改进,其四、五协调的计算误差由原来梁模型的20%.以上降低到5%以内.而且由于计算模型简单,原始数据准备方便,计算时间短的特点,适宜在国产中小型计算机上实施.因而该计算模型可供设计部门在船舶设计阶段较为精确地计算船舶振动特性使用.     

Qualitative Analysis of Bifurcating Solutions in the Lengyel-Epstein Model

One of the most fundamental problems in theoretical biology is to explain the mechanisms by which patterns and forms are created in the＇living world. In his seminal paper ＂The Chemical Basis of Morphogenesis＂, Turing showed that a system of coupled reaction-diffusion equations can be used to describe patterns and forms in biological systems. However, the first experimental evidence to the Turing patterns was observed by De Kepper and her associates（1990） on the CIMA reaction in an open unstirred reactor, almost 40 years after Turing＇s prediction. Lengyel and Epstein characterized this famous experiment using a system of reaction-diffusion equations. The Lengyel-Epstein model is in the form as follows     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

(0,1 ;0)-INTERPOLATION ON INFINITE INTERVAL (-∞, +∞)

In this paper, we study the explicit representation and convergence of (0, 1; 0)-interpolation on infinite interval, which means to determine a polynomial of degree ≤ 3n - 2 when the function values are prescribed at two set of points namely the zeros of Hn(x) and H′n(x) and the first derivatives at the zeros of H′n(x).     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

CONTENTS OF VOLUME 30

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Instructions for contributions

正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with     

Journal of Mathematical Research with Applications Guide for Authors

正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.     

Staircase transportation problems with superadditive rewards and cumulative capacities

A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].