Designs for estimating an extremal point of quadratic regression models in a hyperball

This paper is devoted to studying optimal designs for estimating an extremal point of a multivariate quadratic regression model in the unit hyperball. The problem of estimating an extremal point is reduced to that of estimating certain parameters of a corresponding nonlinear (in parameters) regression model. For this reduced problem truncated locally D-optimal designs are found in an explicit form. The result is a generalization of the results of Fedorov and Müller (1997) for onedimensional quadratic regression function in the unit segment. Received February 2002     

对我国医药企业自主创新演化机制的分析

自主创新是当前商业界和学术界研究比较热的话题。政府相应地制定了一系列的政策和法规来鼓励企业进行自主创新。在这种背景下,我国的医药企业也积极响应国家的政策进行自主创新。然而,医药企业创新在实际操作中的行动方向差异很大。针对这种差异,笔者将医药企业创新划分成新功能创新和新设计创新两种,并且通过对一系列的数据和资料分析后,发现我国的医药企业的创新并非实质上的自主创新即新功能创新,而是新设计创新。文中对产生这种局面的演化机制进行了分析。     

Exact and approximate D-optimal designs in polynomial regression

If the sample sizen is large enough, then the exact polynomial regression designs obtained by rounding the weights of the approximate D-optimal design to integral multiples of 1/n are D-optimal. This was shown by alaevskiî (1966) and Gaffke (1987). In this note, an efficient algorithm to determine the minimum sample sizen _d for a polynomial model of degreed is derived from a condition given by Huang (1987). Under an additional assumption we show that the conditions of Gaffke and Huang are equivalent; we verify the additional assumption for polynomial degreed40.     

环境景观设计中的城市记忆

我国国民经济的持续增长和城市化进程的加快,带来了城市建设的高速发展.但随之而来也产生了一系列问题.地方文化以及地域特色的逐渐丧失便属其中之一.作为城市设计重要组成部分的环境景观设计也面临着同样的问题.城市记忆的概念正是在这一特定的时期提出来的.在我国有关城市记忆方面的讨论和实践已经展开.城市记忆有利于改变目前的现状,有利于城市精神的塑造,有利于创造各具特色的城市风貌,有利于联系城市的过去与未来.     

工业产品设计数字化表现的前景探析

文章通过对工业产品设计数字化表现形式资料的收集和整理,结合笔者对工业产品设计数字化的认识和理解,针对如何利用数字化技术,促进未来工业产品设计发展的问题,着重阐述了产品美学和人文精神的意义,提出了具有总结性和前瞻性的初步研究结果,以谋求数字化时代工业设计产业的发展和进步。     

变电站防雷保护

随着智能建筑系统内的电子设备的数量和规模的不断扩大,大量采用计算机技术,而电子设备普遍存在着绝缘强度低,过电压耐受能力差的弱点,当其受到电磁脉冲,特别是闪电电磁脉冲的袭击,使得这些电子系统在运行时,出现不同程度的运行故障;给工业生产以及人们日常生活造成巨大损失。因此智能建筑物系统内的防雷措施显得尤为重要。     

高层公寓楼的给水和消防设计

城市用地的紧张促使高层建筑越来越多,而高层建筑的给水和消防对住户而言越来越重要,因此在设计中应摆脱以往小高层和多层的固有设计思路和方法。文章从实际案例出发,简述在高层公寓楼给水和消防设计中应注意的问题。     

Optimal designs for generalized linear models with biased response

This paper is concerned with the search for locally optimal designs when the observations of the response variable arise from a weighted distribution in the exponential family. Locally optimal designs are derived for regression models in which the response follows a weighted version of Normal, Gamma, Inverse Gaussian, Poisson or Binomial distributions. Some conditions are given under which the optimal designs for the weighted and original (non-weighted) distributions are the same. An efficiency study is performed to find out the behavior of the D-optimal designs for the original distribution when they are used to estimate models with weighted distributions.     

Performance of empirical Bayes estimators of random coefficients in multilevel analysis: Some results for the random intercept-only model

For a multilevel model with two levels and only a random intercept, the quality of different estimators of the random intercept is examined. Analytical results are given for the marginal model interpretation where negative estimates of the variance components are allowed for. Except for four or five level-2 units, the Empirical Bayes Estimator (EBE) has a lower average Bayes risk than the Ordinary Least Squares Estimator (OLSE). The EBEs based on restricted maximum likelihood (REML) estimators of the variance components have a lower Bayes risk than the EBEs based on maximum likelihood (ML) estimators. For the hierarchical model interpretation, where estimates of the variance components are restricted being positive, Monte Carlo simulations were done. In this case the EBE has a lower average Bayes risk than the OLSE, also for four or five level-2 units. For large numbers of level-1 (30) or level-2 units (100), the performances of REML-based and ML-based EBEs are comparable. For small numbers of level-1 (10) and level-2 units (25), the REML-based EBEs have a lower Bayes risk than ML-based EBEs only for high intraclass correlations (0.5).