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41.
《Analytical letters》2012,45(9):979-993
Abstract Transformation of data with skew distributions into symmetrie ones is an important aid by evaluation of histograms and accentuates class groupings in multivariate principal components analysis. 相似文献
42.
Abstract The thermoelectric and galvanomagnetic properties in the CdxHg1_xTe solid solution samples (x = 0.12; 0.15) irradiated at 300 K by electrons (3.5 MeV; by integrated fluxes up to 1.46 × 1018e/cm2) have been investigated in a wide temperature range 4.2–300 K and in magnetic fields 0–22 kOe. It has been discovered that the electron irradiation of CdxHg1–xTe crystals leads to an increase of the Hall coefficient and a decrease of the thermo e.m.f. sign inversion temperature. The concentrations and mobilities of electron and hole have been calculated on a basis of quantitative analysis of galvanomagnetic data. It has been shown that the kinetic coefficient behavior upon irradiation is due to the Te vacancy-based type radiation defect origin. 相似文献
43.
本文给出一般形式下斜正态随机向量及其平方型的矩公式. 作为应用, 计算出了斜正态随机向量的多元偏度和峰度. 相似文献
44.
含有交易成本的均值-方差-偏度资产组合优化模型 总被引:2,自引:0,他引:2
提出了含有交易成本的均值 -方差 -偏度资产组合优化模型 ;结合一个非对称性收益分布的具体例子 ,对模型做了灵敏度分析 . 相似文献
45.
Tapan Kumar Kar K. S Chaudhuri 《International Journal of Mathematical Education in Science & Technology》2013,44(3):403-416
Bioeconomic exploitation of a prey-predator fishery is discussed by using a reasonable catch-rate function instead of the usual 'catch-per-unit-effort hypothesis'. The model is based on the assumption that only the prey species is harvested. A regulatory agency controls exploitation of the fishery by imposing a tax per unit biomass of the landed fish. The fishing effort is taken as a dynamic variable depending on the capital invested in the fishery. The dynamical system consisting of the growth equations of the species and also the fishing effort is formulated. The existence and stability of steady states are discussed. The optimal tax policy is studied with the help of Pontryagin's maximum principle. Finally, some numerical examples are carried out to illustrate the results of the model. 相似文献
46.
Qian Jian 《Acta Mechanica Sinica》1994,10(1):12-15
Using nonequilibrium statistical mechanics closure method, it is shown that the skewness factor of the velocity derivative
of isotropic turbulence approaches a constant −0.515 when the Reynolds number is very high, which is in agreement with the
DNS (direct numerical simulation) result of Vincent and Meneguzzi (1991).
The project supported by the National Basic Research Program “Non-linear Science” 相似文献
47.
One concern of many investors is to own the assets which can be liquidated easily. Thus, in this paper, we incorporate portfolio liquidity in our proposed model. Liquidity is measured by an index called turnover rate. Since the return of an asset is uncertain, we present it as a trapezoidal fuzzy number and its turnover rate is measured by fuzzy credibility theory. The desired portfolio turnover rate is controlled through a fuzzy chance constraint. Furthermore, to manage the portfolios with asymmetric investment return, other than mean and variance, we also utilize the third central moment, the skewness of portfolio return. In fact, we propose a fuzzy portfolio mean–variance–skewness model with cardinality constraint which combines assets limitations with liquidity requirement. To solve the model, we also develop a hybrid algorithm which is the combination of cardinality constraint, genetic algorithm, and fuzzy simulation, called FCTPM. 相似文献
48.
目前,在Markowitz的均值-方差模型基础上对含有偏度和交易成本模型的研究较少,结合国内市场数据进行研究并做出三维投资组合有效前沿图像的成果更少。在建立两种在交易成本约束条件下以方差和偏度的线性组合为目标函数的最优投资组合模型之后,利用线性函数逼近,将模型转换成线性规划问题,而且这种逼近程度可以控制。用单纯形法求解以得到最优投资组合。利用国内八个上市公司的数据进行实证分析,做出了三维投资组合近似有效前沿图像,并讨论了目标函数最优值和参数的关系。可以发现,目标函数是期望r和参数m的增函数。 相似文献
49.
M.S. Srivastava 《Statistics & probability letters》1984,2(5):263-267
Using principal components, a measure of skewness and kurtosis is developed for multivariate populations. The sample analogues of these measures are proposed as tests of multivariate normality. Also, a graphical method is presented for assessing multivariate normality. 相似文献
50.
Jun Zhang 《Annals of the Institute of Statistical Mathematics》2007,59(1):161-170
The family of α-connections ∇(α) on a statistical manifold equipped with a pair of conjugate connections and is given as . Here, we develop an expression of curvature R
(α) for ∇(α) in relation to those for . Immediately evident from it is that ∇(α) is equiaffine for any when are dually flat, as previously observed in Takeuchi and Amari (IEEE Transactions on Information Theory 51:1011–1023, 2005). Other related formulae are also developed.
The work was conducted when the author was on sabbatical leave as a visiting research scientist at the Mathematical Neuroscience
Unit, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan. 相似文献