近代中国邮政职工(1896-1949)研究综述

近代中国邮政职工是邮政事业的执行者和运行主体,在邮政发展的进程中起到了至关重要的作用?目前,对近代中国邮政职工的研究比较薄弱,其研究成果大多集中于邮政职工的管理?邮政职工运动?邮政职工团体组织?邮政职工抗日斗争等方面,在研究跨度?研究深度和研究广度等方面都存在一定的缺憾和不足,尚存较大的发展空间?可通过拓展研究内容,深入挖掘和运用档案?报刊?电子数据库等资料,不断丰富研究方法,将近代中国邮政职工的研究推向更高层次?     

Nonstationary Binary Choice

This paper develops an asymptotic theory for time series binary choice models with nonstationary explanatory variables generated as integrated processes. Both logit and probit models are covered. The maximum likelihood (ML) estimator is consistent but a new phenomenon arises in its limit distribution theory. The estimator consists of a mixture of two components, one of which is parallel to and the other orthogonal to the direction of the true parameter vector, with the latter being the principal component. The ML estimator is shown to converge at a rate of n^3/4 along its principal component but has the slower rate of n^1/4 convergence in all other directions. This is the first instance known to the authors of multiple convergence rates in models where the regressors have the same (full rank) stochastic order and where the parameters appear in linear forms of these regressors. It is a consequence of the fact that the estimating equations involve nonlinear integrable transformations of linear forms of integrated processes as well as polynomials in these processes, and the asymptotic behavior of these elements is quite different. The limit distribution of the ML estimator is derived and is shown to be a mixture of two mixed normal distributions with mixing variates that are dependent upon Brownian local time as well as Brownian motion. It is further shown that the sample proportion of binary choices follows an arc sine law and therefore spends most of its time in the neighborhood of zero or unity. The result has implications for policy decision making that involves binary choices and where the decisions depend on economic fundamentals that involve stochastic trends. Our limit theory shows that, in such conditions, policy is likely to manifest streams of little intervention or intensive intervention.