On exact D-optimal designs with 2 two-level factors and n autocorrelated observations

In this paper we consider the exact D-optimal designs for estimation of the unknown parameters in the two factors, each at only two-level, main effects model with autocorrelated errors. The vector of the n random errors in the observed responses is assumed to follow a first-order autoregressive model (AR(1)). The exact D-optimal designs seek the optimal combinations of the design levels as well as the optimal run orders, so that the determinant of the information matrix of BLUEs for the unknown parameters is maximized. Bora-Senta and Moyssiadis (1999) gave some conjectures about the exact D-optimal designs based on their experience of several exhaustive searches. In this paper their conjectures are partially proved to be true.Received: January 2003 / Accepted: October 2003Partially supported by the National Science Council of Taiwan, R.O.C. under grant NSC 91-2115-M-008-013.Supported in part by the National Science Council of Taiwan, R.O.C. under grant NSC 89-2118-M-110-003.     

基于EAI构建企业外部服务平台

企业信息化过程逐步从优化内部管理转向提高外部服务，许多企业开始实施CRM和SCM，并进而实现B2B电子商务。EAI的目标是实现企业不同系统之间的集成，通过EAI的实施，可以使企业服务系统获得以ERP为代表的企业后台系统的支撑。     

CMM模型和我国软件业生产过程标准化

CMM模型是国际上最流行的一种软件生产过程标准。本文比较了国内外软件业生产过程标准化的现状,分析了阻碍我国软件业开展CMM评估的原因,并在此基础上,提出在我国推行CMM标准亟待解决的几个主要问题。     

融入长三角 整合区域经济

融入长三角和都市圈、沿江开发等课题,其实质都在区域经济的整合。这是传统计划体制造成行政分割面临市场化、全球化的产物,要经历一个较长过程,才能实现一体化的目标。行政区划与区域整合之间有博奕,出路在于把地方利益与国家利益、人民利益融合起来。目前已在启动,各地不断创新,具体路径宽广,亟待进一步探索。     

工序能力指数的新定义及其应用

本文简述工序能力指数的传统定义及其不合理性,其根源是偏移系数的定义有缺陷。改进偏移系数的定义后,将使工序能力指数的定义更加科学、合理,进而给出不合格品率p与C_p、k之间的计算公式和常用数值表,供企业应用时选用。     

基于改进遗传算法的生鲜加工配送中心连续选址模型

建立了生鲜加工配送中心选址连续模型，在引入监控算子的基础上，运用改进的遗传算法对模型进行求解。该模型和改进的遗传算法可有效的解决生鲜加工配送中心的选址问题。     

绿色物流在化工生产过程中实现途径的探讨

文章从化工生产过程及其物流的特点出发,结合广义绿色物流的观点,提出化工生产物流走绿色物流之路的必要性,并探讨了化工生产实现绿色物流的途径。     

基于模糊层次分析法的企业人力资源风险因素评价

文章结合三角模糊数和层次分析法,以企业外部环境、内部环境及人力资源个人3个方面的11个因素为指标体系,建立模糊层次分析模型,采用三角模糊数表示专家的判断信息,加权平均综合多名专家意见,利用层次分析法对专家判断结果进行处理从而得出各个评价因素的相对权重的大小,并举例说明了模型的应用。     

Testing for unit roots in time series models with non-stationary volatility

Many of the key macro-economic and financial variables in developed economies are characterized by permanent volatility shifts. It is known that conventional unit root tests are potentially unreliable in the presence of such behaviour, depending on a particular function (the variance profile) of the underlying volatility process. Somewhat surprisingly then, very little work has been undertaken to develop unit root tests which are robust to the presence of permanent volatility shifts. In this paper we fill this gap in the literature by proposing tests which are valid in the presence of a quite general class of permanent variance changes which includes single and multiple (abrupt and smooth-transition) volatility change processes as special cases. Our solution uses numerical methods to simulate the asymptotic null distribution of the statistics based on a consistent estimate of the variance profile which we also develop. The practitioner is not required to specify a parametric model for volatility. An empirical illustration using producer price inflation series from the Stock–Watson database is reported.     

建设城市中小型污水处理厂的方案选择

文章首先对城市污水处理厂二级处理的工艺选择及设计方案进行了探讨然后对经常采用的处理工艺进行了技术经济比较。