Production planning and control within a CIM environment: some current developments and requirements for the future

Abstract. This paper considers the integration problems associated with incorporating production planning and control (PP&C) systems within CIM; these problems are typically not differentiated from functionally related problems, and have in the past received relatively little attention. The on-going emergence of a number of standards relevant to manufacturing software systems provides an opportunity to assess the current situation with regard to proprietary PP&C systems and to suggest ways forward towards ‘seamless’ integration of PP&C within the CIM environment. The problems arising from conventional integration approaches are briefly described, and the concept of a simplifying ‘integration platform’ is introduced; the three-schema information architecture is presented as part of this ‘integration simplification’ approach. Current and developing PP&C systems are assessed against a number of information system integration criteria, and the results of a small survey of proprietary packages are presented. The paper concludes that information must be regarded as an enterprise-wide asset, rather than belonging to individual software applications, and that the adoption of relevant standards will enable seamless integration within a three-schema architecture. An increasing number of proprietary packages are adopting standards and methodologies which ease the integration problem significantly.     

Bayes designs for multiple linear regression on the unit sphere

We deal with experimental designs minimizing the mean square error of the linear BAYES estimator for the parameter vector of a multiple linear regression model where the experimental region is the k-dimensional unit sphere. After computing the uniquely determined optimum information matrix, we construct, separately for the homogeneous and the inhomogeneous model, both approximate and exact designs having such an information matrix.     

An efficient sequential design of clinical trials

We propose an efficient group sequential monitoring rule for clinical trials. At each interim analysis both efficacy and futility are evaluated through a specified loss structure together with the predicted power. The proposed design is robust to a wide range of priors, and achieves the specified power with a saving of sample size compared to existing adaptive designs. A method is also proposed to obtain a reduced-bias estimator of treatment difference for the proposed design. The new approaches hold great potential for efficiently selecting a more effective treatment in comparative trials. Operating characteristics are evaluated and compared with other group sequential designs in empirical studies. An example is provided to illustrate the application of the method.     

改进生态足迹模型在湖北省可持续发展研究中的应用

通过调整均衡因子以及引入水资源足迹和环境负荷等对传统生态足迹模型进行了改进,并首次运用改进生态足迹模型对湖北省1997-2006年、中部六省和全国2006年生态足迹及生态承载力进行了计算和基于多种指标的分析.结果显示,与传统模型相比,改进生态足迹模型能更真实、全面地反映区域生态足迹的供需状况和可持续发展程度.     

Improving the Efficiency of the Nelson–Aalen Estimator: the Naive Local Constant Estimator

Abstract.  The Nelson–Aalen estimator is well known to be an asymptotically efficient estimator of the cumulative hazard function, see Andersen et al. ( Statistical models based on counting processes , Springer-Verlag, New York, 1993) among many others. In this paper, we show that the efficiency of the Nelson–Aalen estimator can be considerably improved by using more information in the estimation process than the traditional Nelson–Aalen estimator uses. While our approach results in a biased estimator, the variance improvement is substantial. By optimizing the balance between the bias loss and the variance improvement, we obtain results on the efficiency gain. Several examples for known failure time distributions are used to illustrate these ideas.     

SOME SECOND ORDER ASYMPTOTICS IN EXPONENTIAL FAMILY NON-LINEAR REGRESSION MODELS (A GEOMETRIC APPROACH)

The differential geometric framework of Amari (1982a, 1985) is applied to the study of some second order asymptotics related to the curvatures for exponential family nonlinear regression models, in which the observations are independent but not necessarily identically distributed. This paper presents a set of reasonable regularity conditions which are needed to study asymptotics from a geometric point of view in regression models. A new stochastic expansion of a first order efficient estimator is derived and used to study several asymptotic problems related to Fisher information in terms of curvatures. The bias and the covariance of the first order efficient estimator are also calculated according to the expansion.     

糖酵解反应模型双曲型反应-扩散方程的稳定性和化学振荡

研究了糖酵解反应模型（修正Ｓｅｌｋｏｖ模型）双曲型反应－扩散方程的稳定性和化学振荡．与抛物型方程的结果比较表明，抛物型系统是双曲型系统当反应－扩散数增至无穷大时的特殊情况；双曲型系统不存在波速可能趋于无穷大的问题；二者的稳定性区域存在很大区别；双曲型系统更适合于用来研究糖酵解反应中的化学振荡．     

我国转基因作物产业化的法治管理现状及对策——基于美国转基因稻米污染事件的分析

美国发生的转基因稻米LLRICE601污染事件引起了世界各国的广泛关注。美国健全的法律制度，使该事件的处理具有完善的制度保证。我国在转基因作物产业化过程中存在着制度缺乏和执法不严的问题。我国应构建转基因作物产业化安全评价制度、公众参与制度和救济赔偿制度，实现转基因作物技术的可持续发展。     

An EM Algorithm for Smoothing the Self-consistent Estimator of Survival Functions with Interval-censored Data

Interval-censored data arise in a wide variety of application and research areas such as, for example, AIDS studies (Kim et al ., 1993) and cancer research (Finkelstein, 1986; Becker & Melbye, 1991). Peto (1973) proposed a Newton–Raphson algorithm for obtaining a generalized maximum likelihood estimate (GMLE) of the survival function with interval-cen sored observations. Turnbull (1976) proposed a self-consistent algorithm for interval-censored data and obtained the same GMLE. Groeneboom & Wellner (1992) used the convex minorant algorithm for constructing an estimator of the survival function with "case 2" interval-censored data. However, as is known, the GMLE is not uniquely defined on the interval [0, ∞]. In addition, Turnbull's algorithm leads to a self-consistent equation which is not in the form of an integral equation. Large sample properties of the GMLE have not been previously examined because of, we believe, among other things, the lack of such an integral equation. In this paper, we present an EM algorithm for constructing a GMLE on [0, ∞]. The GMLE is expressed as a solution of an integral equation. More recently, with the help of this integral equation, Yu et al . (1997a, b) have shown that the GMLE is consistent and asymptotically normally distributed. An application of the proposed GMLE is presented