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41.
Accurate forecast of the carbon trading price is of great significance in promoting the scientific and rational development of carbon trading market. Therefore, this paper proposes a multi-scale combined forecasting method for carbon price based on mixed structure data. First, the Google Index is used to extract the unstructured data related to the carbon price.The dimensions of unstructured data are reduced based on principal component analysis. Then, EMD is employedto the structured data,unstructured data and the carbon trading price to obtain different IMFs, which are reconstructed by the Fine-to-Coarse technique to get low, high frequency sequence and trend sequence. Furthermore, the three items are predicted respectively by using ARIMA, PLS and neural networks according to the features of each scale in time series. Finally, the forecasting results are summed to get the carbon price forecast sequence. The proposed method is used to forecast carbon price in EU. The empirical results show that the prediction accuracy of the model is higher than that of the single prediction method and the prediction method that time series aren’t decomposed by EMD, which is of great applicability. 相似文献
改革开放以来,伴随着流动人口规模的剧增,其内部的收入差距现象也逐渐出现。基于2015年流动人口动态监测调查数据,采取Oaxaca-Blinder分解和基于RIF回归的分解探究了不同户籍流动人口收入差距的影响因素,发现相对于性别、年龄等其他变量而言,教育对流动人口城乡收入差距的作用最大,表现为教育的价格效应与结构效应都扩大了收入差距,且前者是最主要的因素,尤其体现在第90分位点,暗含着城乡流动人口的收入差距主要由教育的高回报率所致。进一步研究发现,按照不同年份、年龄以及地区进行划分后的结果各异,但是教育价格效应依然较大。这说明,城乡教育资源发生扭曲的结果只是使得城镇常住人口获得更多了优质教育资源,接受了更多教育。城镇常住人口具有更强的社会网络和城乡教育资源是发生扭曲的并列原因。基于此结果,政府应推进户籍制度的改革,保障教育资源均衡化,加大扶持偏远地区经济发展。同时,农村流动人口也应通过职业培训或继续教育等形式增强自身竞争力。 相似文献
43.
Tatiene C. Souza Tarciana L. Pereira Francisco Cribari-Neto Verônica M. C. Lima 《统计学通讯:模拟与计算》2016,45(2):625-642
We consider testing inference in inflated beta regressions subject to model misspecification. In particular, quasi-z tests based on sandwich covariance matrix estimators are described and their finite sample behavior is investigated via Monte Carlo simulations. The numerical evidence shows that quasi-z testing inference can be considerably more accurate than inference made through the usual z tests, especially when there is model misspecification. Interval estimation is also considered. We also present an empirical application that uses real (not simulated) data. 相似文献
44.
钟海权 《西南石油大学学报(社会科学版)》2016,25(6):87-89
为了开发大型贯流式水轮发电机组径向轴承,在试验台上采用了360的模型轴承对1740可倾6瓦块原型轴承进行模拟试验研究,最高试验比压3.37 MPa、最低线速度3.77 m/s、最高线速度22.62 m/s。试验表明:载荷、进油压力、转速、进油温度和安装间隙比等,对轴承油温升、油流量、功耗、瓦温及油膜厚度等都存在不同程度的影响,其中载荷和转速的影响比较显著。按照模型轴承指导设计的红岩子机组1740轴承已在电站可靠运行,同时开发了径向轴承热弹流计算程序,可以预测径向轴承的油膜压力、油膜温度、油膜厚度、损耗、流量等参数。 相似文献
45.
Hadi Emami 《统计学通讯:理论与方法》2014,43(6):1050-1060
To assess the influence of observations on the parameter estimates, case deletion diagnostics are commonly used in linear regression models. For linear models with correlated errors we study the influence of observations on testing a linear hypothesis using single and multiple case deletions. The change in likelihood ratio test and F test theoretically is derived and it is shown these tests to be completely determined by two proposed generalized externally studentized residuals. An illustrative example of a real data set is also reported. 相似文献
46.
《Journal of Statistical Computation and Simulation》2012,82(3):237-251
In the recovery of interblock information to improve the treatment differences estimates in incomplete block designs, the parameter p is usually unknown. Many authors have worked on the problem of estimating it and of studying its properties together with the properties of the treatment differences estimates. In this paper a numerically efficient algorithm is developed which yields the maximum likelihood estimates (MLE) of all the parameters in the mixed incomplete block design model (treatment effects, ρ and variance) 相似文献
47.
Nilgun Ozgul 《统计学通讯:理论与方法》2019,48(6):1481-1492
In recent years, calibration estimation has become an important field of research in survey sampling. This paper proposes a new calibration estimator for the population mean in the presence of two auxiliary variables in stratified sampling. The theory of new calibration estimator is given and optimum calibration weights are derived. A simulation study is carried out to performance of the proposed calibration estimator over other existing calibration estimators. The results reveal that the proposed calibration estimators are more efficient than other existing calibration estimators in stratified sampling. 相似文献
48.
Nirodha Epasinghe 《统计学通讯:模拟与计算》2017,46(7):5610-5626
It is essential to test the goodness of fit of the model before making inferences based on it. Multilevel modeling of ordinal categorical responses is not as developed as for continuous responses. Assessing model adequacy in terms of the goodness of fit with ordinal categorical responses is still being developed and no satisfactory tests are available so far. As a consequence of that, this study concentrates on developing such a goodness of fit test for Multilevel Proportional Odds models and to study the properties of the test. 相似文献
49.
This work presents a study about the smoothness attained by the methods more frequently used to choose the smoothing parameter in the context of splines: Cross Validation, Generalized Cross Validation, and corrected Akaike and Bayesian Information Criteria, implemented with Penalized Least Squares. It is concluded that the amount of smoothness strongly depends on the length of the series and on the type of underlying trend, while the presence of seasonality even though statistically significant is less relevant. The intrinsic variability of the series is not statistically significant and its effect is taken into account only through the smoothing parameter. 相似文献
50.
Toxicologists and pharmacologists often describe toxicity of a chemical using parameters of a nonlinear regression model. Thus estimation of parameters of a nonlinear regression model is an important problem. The estimates of the parameters and their uncertainty estimates depend upon the underlying error variance structure in the model. Typically, a priori the researcher would not know if the error variances are homoscedastic (i.e., constant across dose) or if they are heteroscedastic (i.e., the variance is a function of dose). Motivated by this concern, in this paper we introduce an estimation procedure based on preliminary test which selects an appropriate estimation procedure accounting for the underlying error variance structure. Since outliers and influential observations are common in toxicological data, the proposed methodology uses M-estimators. The asymptotic properties of the preliminary test estimator are investigated; in particular its asymptotic covariance matrix is derived. The performance of the proposed estimator is compared with several standard estimators using simulation studies. The proposed methodology is also illustrated using a data set obtained from the National Toxicology Program. 相似文献