Firstly, we calculated several statistics relating to the population forecast. Secondly, ba-sed on the Logistic prediction models, against Logistic model defects, we obtained the improved prediction model. Finally, using China's total population in 2004 as the initial population, we predict the total population of China in the next 30 years and in 2050 year by applying the model.

This paper studies the quasi-maximum likelihood estimator (QMLE) for the generalized autoregressive conditional heteroscedastic (GARCH) model based on the Laplace (1,1) residuals. The QMLE is proposed to the parameter vector of the GARCH model with the Laplace (1,1) rstly. Under some certain conditions, the strong consistency and asymptotic normality of QMLE are then established. In what follows, a real example with Laplace and normal distribution is analyzed to evaluate the performance of the QMLE and some comparison results on the performance are given. In the end the proofs of some theorem are presented.

Based on two traffic accident data, during the accident occur and evacuation, we analyze the changing process of the actual traffic capacity on cross-section where the accident happened. We can get the vehicle actual traffic capacity in Accident 2 is larger than the vehicle actual traffic capacity in Accident 1. And build a mathematical vehicle queue length model.

The paper studies the estimation and the portmanteau test for double model with distribution. The double model is investigated to propose firstly the quasi-maximum exponential likelihood estimator, design a portmanteau test of double on the basis of autocorrelation function, and then establish some asymptotic results. Finally, an empirical study shows that the estimation and the portmanteau test obtained in this paper are very feasible and more effective.