基于主成分分析法的综合评价方法的改进

针对用主成分分析法做综合评价存在的问题,提出了改进的方法即当第一主成分的综合评价值和熵值法得到的综合评价值具有一致性时,将两种评价结果进行集成综合评价,若两种评价结果不具有一致性时则采用主成分聚类法进行综合评价.     

关于主成分分析综合评价函数质疑的讨论

主成分分析综合评价是国内较流行的一种综合评价方法,这里对主成分分析综合评价函数的五个质疑或断言,用主成分分析模型、主成分分析综合评价的合理性条件进行了讨论,结果:主成分分析综合评价函数是果,主成分及其包含的信息是因,不能用它们包含的信息比较后推断,因果关联的它们既应分别深入分析,又应结合分析,效果会更好.并结合实例说明:具有合理性条件的主成分分析综合评价改进步骤,更具有合理性和有效性.     

对应用主成分法进行综合评价的探讨

本文针对用主成分法进行综合评价时存在的缺点,提出了分组主成分评价法。即先用因子分析法对变量进行分组后,然后再分别对各组变量进行主成分评价,既保证了主成分法的优点,也克服它在评价中的缺点,提高综合评价结果的合理性。并用该方法对实例进行了分析,取得了较好的效果。     

关于主成分分析做综合评价的改进

本文结合具体事例 ,讨论并改进利用主成分分析做综合评价的方法。     

广西地区经济指标评价

杨善朝，李志友．广西地区经济指标评价．数理统计与管理，１９９７，１６，（４），１～４本文试用主成分分析方法，对广西七个地区的经济生产情况作出综合评价，分析各地区在广西的经济地位。并提出了一种构造加权综合量的方法     

学生成绩的学分绩与主成分排序模型

利用多元统计中的主成分分析研究学生成绩,发现第一主成分排序与学分绩排序结果基本相同,提出用第一主成分代替学分绩对学生进行综合评价更加合理.而且主成分还能反映教学过程中的优点和不足.对教学有一定的指导意义.     

基于主成分分析的建筑工程成本影响因素分析

影响建筑工程成本的因素众多,这些因素在某种程度上是相关联的,甚至有些是冗余的.运用主成分分析法对影响建筑工程成本的因素进行归纳分析,将影响建筑工程成本17个因素通过主成分分析用5个主成分表示并构造出影响建筑工程成本的主成分综合评价函数,使在工程成本领域多维指标实现综合分析得以实现,为建筑工程成本的研究提供参考.     

简约指标体系下我国省级信息化水平综合评价——基于相关分析和主成分分析方法

在海选省级信息化初始评价指标的基础上,采用相关分析和主成分分析定量筛选方法对初始指标体系进行变量筛选;保证筛选出的指标对评价结果有显著影响的前提下,构建了省级信息化评价简约指标体系;用22%的指标反映了99%的原始信息.最后综合各主成分构造的综合评价模型对我国31个省的信息化水平进行了实证分析,得到了较好的评价结果.     

产业集群创新能力评价模型的比较研究

针对产业集群创新能力评价的一些复杂方法,以文献中的基于BP神经网络的产业集群创新能力评价模型作为比较对象,提出了两种评价模型:组合评价模型和主成分指数模型.前者将变异系数法和Topsis法组合使用,用以评价产业集群创业能力;后者则是对所有参评样本的评价指标进行主成分分析,以主成分的方差贡献率为权重,构建主成分综合指数,从而形成产业集群创新能力的综合评价指数模型.对这两个模型用来自比较对象模型的同一数据进行了验证,三个模型都得出了非常相近的结果,而这两种模型更具可操作性且易于解释,这两者相比,主成分分析的方法则更为简单易行.     

城市环境质量多元统计分析──永安市城市环境质量综合评价

本文针对永安市城市环境质量综合评价，采用主成分分析法［１］，以福建省十个城市为样本进行横向比较，从而揭示永安市环境质量状况及其改进环境质量的突破口．使环境质量现状分析具有评价和控制的双重功能。     

Joint Similarities and Parameterizations for Dilations of Dual g -frame Pairs in Hilbert Spaces

In this paper, we give an operator parameterization for the set of dilations of a given pair of dual g-frames and the set of dilations of pairs of dual g-frames of a given g-frame. In particular, for the dilations of a given pair of dual g-frames, we introduce the concept of joint complementary g-frames and prove that the joint complementary g-frames of a pair of dual g-frames are unique in the sense of joint similarity, which then helps to obtain a sufficient condition such that the complementary g-frames of a g-frame are unique in the sense of similarity and show that the set of dilations of a given dual g-frame pair are parameterized by a set of invertible diagonal operators. For the dilations of pairs of dual g-frames, we prove that the set of dilations of pairs of dual g-frames are parameterized by a set of invertible upper triangular operators.     

Optimization of axisymmetric membrane shells

Problems of the joint optimization of the shape and distribution along the meridian of the thickness of membrane shells of revolution under the action of axisymmetric loads are considered, taking account of the constraints concerning the strength of the shell and the volume of its cavity. General formulations of problems of the optimal design of shells of revolution are given and the optimal shape of a shell and the corresponding thickness distribution are investigated. Results of the exact solution of problems of the optimal design of closed shells of revolution when there is an internal pressure are presented. The simultaneous introduction of two control functions, describing the shape of the shell and the distribution of its thickness, not only ensures a substantial reduction in the mass of a shell but also leads to significant mathematical simplifications, which enable the solution of the optimization problem being considered to be obtained in an analytical form.     

区间数的绝对值与区间值函数的极限

研究了区间数的绝对值和区间值函数的极限问题.首先,讨论了区间数的H-差的性质,得到了H-差的两个运算法则;然后,给出了区间数的绝对值概念,并讨论了区间数绝对值的性质;最后,借助区间数的H-差和绝对值的概念,建立了区间值函数极限概念的一种新的表达方式,给出了极限存在的充分必要条件,证明了极限值的唯一性及对加法运算和数乘运算的封闭性.     

Estimate of the Order of Growth of a Class of Entire Functions on the Real Axis

For a class of entire functions we study the problem of estimation of the order of growth of functions on the real axis. This problem is important for the justification of the integral representation of bounded solutions to certain partial differential equations considered in other papers of the authors. In order to obtain an estimate of the order of growth of a function on the real axis, we use the method of differential equations. The method is based, on one hand, on the construction of a system of first-order ordinary differential equations whose solution is a vector function of traces of function and its derivatives on the real axis. On the other hand, under the respective change of variables in the system of equations, we obtain an estimate of the solution to the system of equations for a large positive values of the argument. The obtained estimate is non-trivial and shows the way a complex parameter of a power series affects the order of growth of a function.     

Damageability of a material reinforced with unidirectional orthotropic fibers for an exponential function of long-term microstrength

The theory of long-term damageability of a homogeneous material is generalized to the case of an orthotropic fibrous composite material with a stochastic structure. Equations of mechanics of microinhomogeneous media of this structure form the base of the theory. The process of damage of components of a composite is modeled by the formation of stochastically located micropores. The criterion of fracture of a unit microvolume is characterized by its long-term strength determined by the dependence of the time of brittle fracture on the degree of closeness of the equivalent stress to its limit value, which characterizes the short-term strength on the basis of the Huber–von Mises criterion accepted as an arbitrary function of coordinates. Efficient deformation properties and the stress-strain state of an orthotropic fibrous composite with microdamages in components are determined on the base of stochastic equations of elasticity of orthotropic media. For given macrostresses and macrostrains and an arbitrary moment of time, balance equations of damage (porosity) of components are formulated. On the basis of the iteration method, we construct algorithms for calculating dependences of microdamage of components of an orthotropic fibrous material on time and dependences of macrostresses or macrostrains on time and obtain the corresponding curves for the case of a bounded function of the long-term microstrength, which is approximated by an exponential law.     

Configurations of ovals

We survey the known hyperovals in . We then survey the relationship of the study of configurations of ovals in called augmented fans to that of ovoids of , flocks of the quadratic cone of , flocks of a translation oval cone of and spreads of certain generalised quadrangles of order. We also consider the configurations of ovals in called herds and their relationship with flocks of the quadratic cone of.     

Geometry of a five link mechanism with two degrees of freedom

The paper is devoted to the solution of straight and inverse geometrical tasks of five link mechanism with two degrees of freedom. The solution of the mentioned problem is very important in order to determine kinematic parameters of actuators. The problem can be divided into two parts. The first part is considered when we are given the coordinates of the output link of the mechanism and the necessity arises of determining the angles of rotation of actuators. On the other hand, it is very important to determine the position of the output link when the angles of rotation of the actuators are known. Here we consider that the mechanism is composed only of five classes of rotating kinematic pairs and the actuators are situated at the junctions of frames and links of the examined mechanism. The solution of the said problem is based on utilization of homogenous coordinates. On the basis of the obtained equations of motion, one can calculate the trajectories of motion of the output link as well angles of rotation of the actuators by taking into consideration preliminary given kinematic parameters of the mechanism. Here we also obtain equations for calculating values of speed and acceleration of the links of the mechanism. The calculations differ from known methods in simplicity and high performance, which would be useful for programming actuators mounted in the joints of the linkage.     

我国医疗费用增长与医疗设备投入的相关性研究

近年来我国卫生总费用占GDP的比例增长很快,而在卫生费用结构上则发生政府投入下降和个人支出的上升。本文采集了大量的统计数据,采用统计相关性研究的方法,论证了医疗设备规模的不断扩大是导致医疗费用上升的主要因素之一;医疗设备的快速增长与医院维修费用投入的增长直接相关,而引起医疗设备维修大量投入的主要原因则是故障期内医疗设备的非正常闲置。本文通过对个人卫生费用的上升、医疗设备规模的扩大及其医疗设备维修投入费用增加相关性的分析,说明了在这种关系下,十分有必要研究医院医疗设备维修体系,以在卫生投入和患者权益上达到平衡。