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基于GRA-DEA模型的有关农民收入的九城市的评价 总被引:1,自引:0,他引:1
王有文 《数学的实践与认识》2018,(6)
有关农民收入,文章以山西省九个城市为例进行了评价.首先用灰色关联分析法分析了2016年这些城市的有关数据,筛选出影响农民收入的主要因素;其次构建了指标体系,利用数据包络分析法对有关农民收入九个城市进行了DEA有效性评价;再次对非DEA有效的城市,借助投影公式探索了改进方法;最后得出了九城市分为两类的结论,提出了针对性的建议. 相似文献
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本文首先介绍了半群、群的定义,研究了自然数n取何值时,通过定义相应的代数运算,使得它的因子集构成半群、群,从而为半群的代数理论提供了一个有趣的实例. 相似文献
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本文利用高斯函数的正整数阶导函数的一个性质,给出了一种探测信号奇异性的方法,得到了奇异点的位置,阶数α以及相应的平滑因子a和k,推导出了α满足的方程,对文献[8]的结论进行了推广.最后进行了数值试验,相对Mallat定理的10%的误差,取得了较好的效果. 相似文献
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本文从实验事实出发,对含有共轭三键的共轭高聚物——聚丁二炔的掺杂及电导的特点进行了详细的分析;对聚丁二炔晶体掺杂的机制进行了初步的探讨;从结构相变的角度出发,提出了一个掺杂模型,并从能量的角度估算了由于掺杂引起链段结构改变所需的能量,较好地解释了聚丁二炔晶体掺杂未取得成功的原因. 相似文献
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A.P. Markeyev 《Journal of Applied Mathematics and Mechanics》2008,72(3):250-258
The stability in the first approximation of the rotation of a satellite about a centre of mass is investigated. In the unperturbed motion the satellite performs, in absolute space, three rotations around the normal to the orbital plane in a time equal to two periods of rotation of its centre of mass in the orbit (Mercury-type rotation). Three cases of such rotations are considered: the rotations of a dynamically symmetrical satellite and a satellite, the central ellipsoid of inertia of which is close to a sphere, in an elliptic orbit of arbitrary eccentricity, and the rotation of a satellite with three different principal central moments of inertia in a circular orbit. 相似文献
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Dorota Kuchta 《Fuzzy Optimization and Decision Making》2007,6(2):173-178
On the basis of a known application of an order weighted averaging operator to the decision making in the case of a discrete
set of states of nature, a general approach to the case of a continuous set of states of nature is proposed. The general approach
encompasses various types of attitudes of the decision maker, expressed in the form of fuzzy numbers. 相似文献
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Mathematicians and mathematics educators agree that proof is an important tool in mathematics, yet too often undergraduate students see proof as a superficial part of the discipline. While proof is often used by mathematicians to justify that a theorem is true, many times proof is used for another purpose entirely such as to explain why a particular statement is true or to show mathematics students a particular proof technique. This paper reports on a study that used a form of inquiry-based learning (IBL) in an introduction to proof course and measured the beliefs of students in this course about the different functions of proof in mathematics as compared to students in a non-IBL course. It was found that undergraduate students in an introduction to proof course had a more robust understanding of the functions of proof than previous studies would suggest. Additionally, students in the course taught using inquiry pedagogy were more likely to appreciate the communication, intellectual challenge, and providing autonomy functions of proof. It is hypothesized that these results are a response to the pedagogy of the course and the types of student activity that were emphasized. 相似文献
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V. P. Stavrov A. V. Markov A. V. Zhernovskii K. F. Friedrich 《Mechanics of Composite Materials》2000,36(3):249-254
The problem of compression of a unidirectional layer and shear of a polymer interlayer during winding of rings is considered.
The equations determining the dependence of the layer thickness and stresses on the parameters entering into the power flow
law for a prepreg and polymer matrix and on the basic parameters of the winding process—the initial tension of the prepreg,
its placement rate, and the radius of a mandrel—are derived. The ring thickness measurements obtained at various temperatures
and initial tension forces of plies confirm the adequacy of the model offered. It is found that the viscous properties of
the prepreg and matrix upon winding affect the relative change in the layer thickness to a greater extent than the stresses
in these layers. With increase in temperature and tension force upon winding, the effect of viscous deformations of the prepreg
and matrix increases. A decrease in viscosity and an increase in the tension force of the tape lead to a higher strength of
the ring in tension and interlaminar shear; however, the growing percolation of the polymer melt leads to a greater inhomogeneity
of the structure of the composite in the ring and to a lower reinforcing effect of the factors mentioned.
Presented at the 11th International Conference on Mechanics of Composite Materials (Riga, June 11–15, 2000).
Translated from Mekhanika Kompozitnykh Materialov, Vol. 36, No. 3, pp. 419–428, 2000. 相似文献
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In this paper we introduce a theory of finite sets FST with a strong negation of the axiom of infinity asserting that every set is provably bijective with a natural number. We study in detail the role of the axioms of Power Set, Choice, Regularity in FST, pointing out the relative dependences or independences among them. FST is shown to be provably equivalent to a fragment of Alternative Set Theory. Furthermore, the introduction of FST is motivated in view of a non-standard development. MSC: 03E30, 03E35. 相似文献
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Nonlinear models are introduced to describe the nonequilibrium dynamics of social evolution. The difference between Western and Oriental culture, and their roles in the origin in the division of labour, are described by a behavioural model in information diffusion and learning competition. It shows a tradeoff between stability and diversity. The stochastic mechanism of social differentiation and the empirical evidence for this is discussed in a stochastic model of multi-staged development. It shows the breakdown of the Gaussian distribution during a transition. Finally, an ideal model of social bifurcation is given. 相似文献
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A. I. Budkin 《Algebra and Logic》2007,46(1):16-27
We fix a universal algebra A and its subalgebra H. The dominion of H in A (in a class M) is the set of all elements a ∈ A such that any pair of homomorphisms f, g: A → M ∈ M satisfies the following: if f and g coincide on H then f(a) = g(a). In association with every quasivariety, therefore, is
a dominion of H in A. Sufficient conditions are specified under which a set of dominions form a lattice. The lattice of dominions
is explored for down-semidistributivity. We point out a class of algebras (including groups, rings) such that every quasivariety
in this class contains an algebra whose lattice of dominions is anti-isomorphic to a lattice of subquasivarieties of that
quasivariety.
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Translated from Algebra i Logika, Vol. 46, No. 1, pp. 26–45, January–February, 2007. 相似文献
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The tail of the distribution of a sum of a random number of independent and identically distributed nonnegative random variables depends on the tails of the number of terms and of the terms themselves. This situation is of interest in the collective risk model, where the total claim size in a portfolio is the sum of a random number of claims. If the tail of the claim number is heavier than the tail of the claim sizes, then under certain conditions the tail of the total claim size does not change asymptotically if the individual claim sizes are replaced by their expectations. The conditions allow the claim number distribution to be of consistent variation or to be in the domain of attraction of a Gumbel distribution with a mean excess function that grows to infinity sufficiently fast. Moreover, the claim number is not necessarily required to be independent of the claim sizes. 相似文献
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Dario De Stavola 《Discrete Mathematics》2018,341(11):3182-3208
Many aspects of the asymptotics of Plancherel distributed partitions have been studied in the past fifty years, in particular the limit shape, the distribution of the longest rows, connections with random matrix theory and characters of the representation matrices of the symmetric group. Regarding the latter, we extend a celebrated result of Kerov on the asymptotic of Plancherel distributed characters by studying partial trace and partial sum of a representation matrix. We decompose each of these objects into a main term and a reminder, and for each such a decomposition we prove a central limit theorem for the main term. We apply these results to prove a law of large numbers for the partial sum. Our main tool is the expansion of symmetric functions evaluated on Jucys–Murphy elements. 相似文献