Almost Consistent Estimation of Panel Probit Models with “Small” Fixed Effects

We propose four different GMM estimators that allow almost consistent estimation of the structural parameters of panel probit models with fixed effects for the case of small Tand large N. The moments used are derived for each period from a first order approximation of the mean of the dependent variable conditional on explanatory variables and on the fixed effect. The estimators differ w.r.t. the choice of instruments and whether they use trimming to reduce the bias or not. In a Monte Carlo study, we compare these estimators with pooled probit and conditional logit estimators for different data generating processes. The results show that the proposed estimators outperform these competitors in several situations.     

A two phases queueing system with Bernoulli vacation schedule under multiple vacation policy

This paper deals with a single server Poisson arrival queue with two phases of heterogeneous service along with a Bernoulli schedule vacation model, where after two successive phases service the server either goes for a vacation with probability p (0≤p≤1) or may continue to serve the next unit, if any, with probability q(=1−p). Further the concept of multiple vacation policy is also introduced here. We obtained the queue size distributions at a departure epoch and at a random epoch, Laplace Stieltjes Transform of the waiting time distribution and busy period distribution along with some mean performance measures. Finally we discuss some statistical inference related issues.     

横向塞曼稳频He－Ne激光器的研究

稳频横向塞曼Ｈｅ－Ｎｅ激光器作为一种新型光源，具有功率大、频差低、易于相位细分的特点，因而能广泛应用于各种精密测量中．本文介绍了我们研制的稳频横向塞曼激光器，实验结果表明，其激光频率稳定度达４．７×１０（－１０），再现性达１．８×１０（－８）．     

Two point priors and Γ-minimax estimating in families of uniform distributions

It is shown that when a parameter lying in a sufficiently small interval is to be estimated in a family of uniform distributions, a two point prior is least favourable under squared error loss. The unique Bayes estimator with respect to this prior is minimax. The Γ-minimax estimator is derived for sets Γ of priors consisting of all priors that give fixed probabilities to two specified subintervals of the parameter space if a two point prior is least favourable in Γ.     

卫星光通信中平台抖动补偿技术研究

以卫星光通信系统为例,对空间光通信系统中光学平台的抖动进行了分析。研究了一种自调节前馈补偿技术,通过自适应信号处理或对前馈控制器进行直接优化,可对光学平台的抖动进行有效抑制。     

宽带卫星通信和星际链路间激光通信的应用前景

提出了由于信息化社会、Ｉｎｔｅｒｎｅｔ、Ｉｎｔｒａｎｅｔ和多媒体技术的出现,从而要求卫星通信向多体制、多功能发展。文中着重分析了具有独特优点的激光通信在宽带卫星通信和星际链路中的现实商用前景。     

空间光通信ATP技术及其进展

对自由空间激光通信光束自动捕获、跟踪、瞄准（ＡＴＰ）系统的结构与系统主要技术指标进行了分析和讨论。通过对其中典型系统的介绍,进一步描述了ＡＴＰ技术的最新进展,论证了空间激光通信的可行性。     

空间光通信ATP系统设计分析

空间光束捕获、跟踪、瞄准（ＡＴＰ）技术在空间光通信中具有重要地位。文中讨论了空间光通信系统中的ＡＴＰ伺服系统的结构,并对系统稳态设计和系统动态综合等关键问题进行了详细的分析和研究。     

半导体激光器的光学准直

对半导体激光器进行光学准直是空间光通信系统必须进行的重要工作。文中简述了准直通常使用的方法,测试了使用单透镜对一种３５ｍＷ半导体激光器的准直结果,准直效率约为６０％,准直后的发射角为０４～０７５ｍｒａｄ。     

Modeling household fertility decisions with generalized Poisson regression

This paper models household fertility decisions by using a generalized Poisson regression model. Since the fertility data used in the paper exhibit under-dispersion, the generalized Poisson regression model has statistical advantages over both standard Poisson and negative binomial regression models, and is suitable for analysis of count data that exhibit either over-dispersion or under-dispersion. The model is estimated by the method of maximum likelihood. Approximate tests for the dispersion and goodness-of-fit measures for comparing alternative models are discussed. Based on observations from the Panel Study of Income Dynamics of 1989 interviewing year, the empirical results support the fertility hypothesis of Becker and Lewis (1973). Received January 7, 1997 /Accepted April 3, 1997