Bayes least squares linear estimation of densities

Linear, least squares statistical methods in which the "parameters" are interpreted as random variables were introduced by Whittle, and further developed by Hartigan and others. They are applied here to the problem of estimating the coefficients in an orthogonal expansion of a multivariate density, given a simple random sample.     

Geometric programming for optimal allocation of integrated samples in quality control

We apply geometric programming, developed by Duffin, Peterson Zener (1967), to the optimal allocation of stratified samples. As an introduction, we show how geometric programming is used to allocate samples according to Neyman (1934), using the data of Cornell (1947) and following the exposition of Cochran (1953).

Then we use geometric programming to allocate an integrated sample introduced by Schwartz (1978) for more efficient sampling of three U. S. Federal welfare quality control systems, Aid to Families with Dependent Children, Food Stamps and Medicaid.

We develop methods for setting up the allocation problem, interpreting it as a geometric programming primal problem, transforming it to the corresponding dual problem, solving that, and finding the sample sizes required in the allocation problem. We show that the integrated sample saves sampling costs.     

Posterior moments of scalar functions of a covariance matrix

Given multivariate normal data and a certain spherically invariant prior distribution on the covariance matrix, it is desired to estimate the moments of the posterior marginal distributions of some scalar functions of the covariance matrix by importance sampling. To this end a family of distributions is defined on the group of orthogonal matrices and a procedure is proposed for selecting one of these distributions for use as a weighting distribution in the importance sampling process. In an example estimates are calculated for the posterior mean and variance of each element in the covariance matrix expressed in the original coordinates, for the posterior mean of each element in the correlation matrix expressed in the original coordinates, and for the posterior mean of each element in the covariance matrix expressed in the coordinates of the principal variables.     

宽带无线通信中的MIMO系统

介绍了多入多出系统中的空时、空频编码技术,并在此基础上将OFDM技术与MIMO系统相结合,研究了STBC-OFDM、SFBC-OFDM及VBLAST-OFDM系统。对该系统性能进行了分析和仿真,结果表明VBLAST系统传输速率最高,其速率至少是分组码MIMO-OFDM系统的2倍,但是其误码性能相对较差,误码率为0.001时,VBLAST-OFDM系统所需的信噪比比分组码系统要高9.3dB。     

《论语》及其英译本中投射语言的人际功能分析

《论语》英译的各种翻译策略已受到越来越多研究者的关注,但《论语》中投射语言翻译研究还未能引起足够的重视。因此,本文运用系统功能语言学的人际功能分析方法,从语气、语气成分、人称等角度探讨与比较了《论语》原文及其四个英译本中投射语言人际意义的实现方式。我们发现,不同译者对投射语言的相关翻译策略不尽相同,这在不同程度上反映了译者由于翻译目的的不同及对原文投射语言人际意义的理解差异,产生了对原文相关投射语言人际意义的认知程度的差异,从而采用了不同的翻译策略。     

新世纪东、中、西部地区可持续发展的人口环境

我国东、中、西部地区的人口、经济和自然环境差别很大。中国政府确立了下世纪实施西部大开发战略。揭示和分析东、中、西部地区人口发展的趋势与差异 ,了解各地区可持续发展的人口环境 ,对于实现我国地区的可持续发展战略是非常必要的。本文按照“七五”期间国家划分的东、中、西部三大区域 ,对 1990～ 2 0 6 0年三大区域的人口发展趋势进行了预测。从人口规模、年龄结构和劳动力资源三个方面对东、中、西部地区发展的人口环境进行了对比分析。     

正交设计优化八氟丙烷白蛋白微球混悬液的制备工艺

目的优化八氟丙烷白蛋白微球混悬液的制备工艺。方法以微球的平均直径和浓度为考察指标，以八氟丙烷通气量、声振强度和终点温度作为工艺条件进行三因素三水平的正交试验。结果最佳工艺条件为采用1％人血白蛋白溶液20 mL，声振强度90％，5 s内通入八氟丙烷2 mL，终点温度77 ℃。结论采用该最佳工艺制备的八氟丙烷白蛋白微球混悬液，微球浓度高而且稳定。     

Two-dimensional projection uniformity for space-filling designs

We investigate a space-filling criterion based on $L_2$-type discrepancies, namely the uniform projection criterion, aiming at improving designs' two-dimensional projection uniformity. Under a general reproducing kernel, we establish a formula for the uniform projection criterion function, which builds a connection between rows and columns of the design. For the commonly used discrepancies, we further use this formula to represent the two-dimensional projection uniformity in terms of the $L_p$-distances of U-type designs. These results generalize existing works and reveal new links between the two seemingly unrelated criteria of projection uniformity and the maximin $L_p$-distance for U-type designs. We also apply the obtained results to study several families of space-filling designs with appealing projection uniformity. Because of good projected space-filling properties, these designs are well adapted for computer experiments, especially for the case where not all the input factors are active.     

紫金砂总香豆素的超声辅助提取工艺研究

目的研究超声辅助提取紫金砂中总香豆素的最佳提取工艺。方法以总香豆素提取率为指标，考察超声提取温度、提取功率、提取时间、料液比、提取次数对紫金砂总香豆素提取的影响。选用正交试验设计法对紫金砂的超声辅助提取工艺进行优选。结果超声辅助提取紫金砂中总香豆素的最佳工艺为：65 ℃，超声功率90 W，以1∶18的料液比加入丙酮，超声提取50 min，提取4 次。结论通过验证实验, 表明所选的工艺条件可行，在该工艺条件下每克紫金砂平均可提取总香豆素27.4 mg-1。