Robust nonparametric estimation with missing data

In this paper, under a nonparametric regression model, we introduce two families of robust procedures to estimate the regression function when missing data occur in the response. The first proposal is based on a local M$M$-functional applied to the conditional distribution function estimate adapted to the presence of missing data. The second proposal imputes the missing responses using the local M$M$-smoother based on the observed sample and then estimates the regression function with the completed sample. We show that the robust procedures considered are consistent and asymptotically normally distributed. A robust procedure to select the smoothing parameter is also discussed.     

教育媒体与技术在机械制图课程教学中的优化运用

为了获得良好的教学效果,提高教育教学质量,关键是如何实现教育媒体与技术在课程教学中的优化运用。文章在调查研究和理论分析的基础上,建立了基于教育媒体与技术的优化教学模型,重点介绍了教育媒体与技术在机械制图课程教学中优化运用的一些做法和经验。     

Optimality Of Some Two-Stage Sampling Methods

Two-stage sampling plans in which the estimator is computed from the second sample only, and has a guaranteed precision irrespective of the parameter value, are considered. We prove the following optimality property for existing strategies in binomial and Poisson populations: there exists no other

strategy, of the same form, that guarantees the same precision, without increasing the expected sample size for some parameter valucs. The method of proof is illustrnted by proving a similar result for normal populations     

A note on nonlinear regression for the autoregressive moving average with non-hd errors

Estimation by nonlinear regression of the parameters for the stationary and invertible autoregressive moving average (ARMA) model with mixing or martingale difference errors is considered. Simple proofs of consistency and asymptotic normality for the nonlinear least squares estimator are given by exploiting results from nonlinear estimation theory and mixing and mixingale theory.     

越障机器人的设计与研究

系统地阐述了越障机器人的机构设计思想及运动原理；分析和探讨了遥控控制手段，控制电路及控制策略，该机器人机构设计巧妙，采用航模比例遥控器和PLC电路进行控制，具有结构紧凑可靠，操作简单，运动灵活等特点，在实践中得到了良好的验证。     

The Statistics of Simulating Chaos

When simulating a dynamical system, the computation is actually of a spatially discretized system, because finite machine arithmetic replaces continuum state space. For chaotic dynamical systems, the discretized simulations often have collapsing effects, to a fixed point or to short cycles. Statistical properties of these phenomena can be modelled with random mappings with an absorbing centre. The model gives results which are very much in line with computational experiments. The effects are discussed with special reference to the family of mappings f (x)=1-|1-2x|,x [0,1],1,<,,<,. Computer experiments show close agreement with predictions of the model.     

Non‐parametric Threshold Estimation for Models with Stochastic Diffusion Coefficient and Jumps

Abstract. We consider a stochastic process driven by diffusions and jumps. Given a discrete record of observations, we devise a technique for identifying the times when jumps larger than a suitably defined threshold occurred. This allows us to determine a consistent non‐parametric estimator of the integrated volatility when the infinite activity jump component is Lévy. Jump size estimation and central limit results are proved in the case of finite activity jumps. Some simulations illustrate the applicability of the methodology in finite samples and its superiority on the multipower variations especially when it is not possible to use high frequency data.     

自旋电子在钙钛矿锰氧化物中输运性质研究

本文对国内外研究钙钛矿锰氧化物磁电性质及CMR效应的现状进行了分析,指出有必要研究自旋电子在钙铁矿锰氧化物中的输运性质与材料的磁性以及外加磁场的关系,并对研究方法进行了探讨。     

On Bayesian estimators in multistage binomial designs

A new class of Bayesian estimators for a proportion in multistage binomial designs is considered. Priors belong to the beta-J distribution family, which is derived from the Fisher information associated with the design. The transposition of the beta parameters of the Haldane and the uniform priors in fixed binomial experiments into the beta-J distribution yields bias-corrected versions of these priors in multistage designs. We show that the estimator of the posterior mean based on the corrected Haldane prior and the estimator of the posterior mode based on the corrected uniform prior have good frequentist properties. An easy-to-use approximation of the estimator of the posterior mode is provided. The new Bayesian estimators are compared to Whitehead's and the uniformly minimum variance estimators through several multistage designs. Last, the bias of the estimator of the posterior mode is derived for a particular case.     

基于Shapley值法的移动增值服务价值链利润分配模型

研究对象为任意节点连接和任意支撑的平面框架。一般梁单元由等截面直杆及其杆端的轴向弹簧、切向弹簧和转动弹簧组成，推导得到此类单元的刚度矩阵、单元在8种基本荷载作用下的等效节点荷载。采用Matlab语言编写了适用于一般节点非线性连接框架的静力分析程序，非线性形式为指数函数或多项式函数，可以得到结构不同连接刚度下的节点位移、杆端位移和杆端力。算例显示出节点柔度对结构受力和变形的影响。