股票价格稳定性的非参数平滑估计

股票的优质性主要由股票价格的稳定性来决定。通过建立条件风险函数非参数平滑估计的估计方法,证明条件风险函数平滑后的非参数估计值具有一致性和渐进正态性,并将此方法扩展到了截尾数据中。通过蒙特卡罗模拟表明条件风险函数平滑后的非参数估计值在非截尾数据以及截尾数据中的有限样本行为都要优于非平滑的估计值。实证分析中用截尾数据条件风险函数非参数平滑估计方法非参数估计中国14大行业股票价格的稳定性,发现房地产行业的股票价格最不稳定,建筑材料行业的股票价格表现最稳定。

Parametric modeling of carbon nanotubes and estimating nonlocal constant using simulated vibration signals-ARMA and ANN based approach

Nonlocal continuum mechanics is a popular growing theory for investigating the dynamic behavior of Carbon nanotubes(CNTs).Estimating the nonlocal constant is a crucial step in mathematical modeling of CNTs vibration behavior based on this theory.Accordingly,in this study a vibration-based nonlocal parameter estimation technique,which can be competitive because of its lower instrumentation and data analysis costs,is proposed.To this end,the nonlocal models of the CNT by using the linear and nonlinear theories are established.Then,time response of the CNT to impulsive force is derived by solving the governing equations numerically.By using these time responses the parametric model of the CNT is constructed via the autoregressive moving average(ARMA)method.The appropriate ARMA parameters,which are chosen by an introduced feature reduction technique,are considered features to identify the value of the nonlocal constant.In this regard,a multi-layer perceptron(MLP)network has been trained to construct the complex relation between the ARMA parameters and the nonlocal constant.After training the MLP,based on the assumed linear and nonlinear models,the ability of the proposed method is evaluated and it is shown that the nonlocal parameter can be estimated with high accuracy in the presence/absence of nonlinearity.