怎样評价一个专家系统

本文首先介绍了专家系统,然后着重介绍了国外评价专家系统的准则。它包括基本特性的估计、开发环境、学习和使用性、成本以及怎样得到支持等,最后将举例说明怎样用这些准则来评价一个实际的专家系统。     

水力发电企业整体效益评价及实例

针对水力发电企业的整体经济效益难以进行评价的问题,提出了以灰色关联度技术为支撑,选择数量模型评价方法,应用层次分析法的有关技术和思想,建立起具有可操作性的评价模型及评价体系。     

塑料注射机节能问题的研究与探讨

本文针对 XS—ZY—125型塑料注射成型机,分析了现行通用的双联泵供油液压系统耗能大的原因。介绍了压力流量补偿负荷传感液压系统在注射机上应用的基本原理。通过应用上述两种液压系统分别驱动同一台注射机的生产运行对比试验和能耗测试分析,证明压力流量补偿负荷传感液压系统具有十分显著的节能效果。通过经济效益估算分析,指出进一步开发压力流量补偿负荷传感液压系统在注射机上的应用,不仅具有十分显著的经济效益,而且具有很大的社会效益。     

机器人、微机和微处理器(RMM)的抗干扰

本文讨论了电磁辐射、电源波动等干扰源,并分析这些干扰源怎样引起机器人控制系统、微机、微处理器的失灵和损坏。最后本文介绍了防止这些干扰的实用方法,它们包括有双层屏蔽、光电隔离、光纤传导等方法。     

网上CAI

用好现代先进技术,开展网络建设,是教育信息化的第一步。本文基于这一思想,介绍了网上CAI的设计思路,描述了该系统的功能,以及实现系统所采用的技术措施。     

青岛一套表的实践与经验

 企业统计一套表一直是统计制度方法改革和实践中的焦点问题。本文通过对青岛市统计局企业一套表制度实施情况的案例分析,系统界定了企业一套表的概念和内涵,全面展现了企业一套表的运作过程,客观分析了制约企业一套表实施的主要原因,并提出了在现阶段实施企业统计一套表的条件和要求。     

A Bayesian discovery procedure

Summary.  We discuss a Bayesian discovery procedure for multiple-comparison problems. We show that, under a coherent decision theoretic framework, a loss function combining true positive and false positive counts leads to a decision rule that is based on a threshold of the posterior probability of the alternative. Under a semiparametric model for the data, we show that the Bayes rule can be approximated by the optimal discovery procedure, which was recently introduced by Storey. Improving the approximation leads us to a Bayesian discovery procedure, which exploits the multiple shrinkage in clusters that are implied by the assumed non-parametric model. We compare the Bayesian discovery procedure and the optimal discovery procedure estimates in a simple simulation study and in an assessment of differential gene expression based on microarray data from tumour samples. We extend the setting of the optimal discovery procedure by discussing modifications of the loss function that lead to different single-thresholding statistics. Finally, we provide an application of the previous arguments to dependent (spatial) data.     

Generalized Augmentation to Control the False Discovery Exceedance in Multiple Testing

Abstract.  A new multiple testing procedure, the generalized augmentation procedure (GAUGE), is introduced. The procedure is shown to control the false discovery exceedance and to be competitive in terms of power. It is also shown how to apply the idea of GAUGE to achieve control of other error measures. Extensions to dependence are discussed, together with a modification valid under arbitrary dependence. We present an application to an original study on prostate cancer and on a benchmark data set on colon cancer.     

A clarifying comparison of methods for controlling the false discovery rate

Traditional multiple hypothesis testing procedures fix an error rate and determine the corresponding rejection region. In 2002 Storey proposed a fixed rejection region procedure and showed numerically that it can gain more power than the fixed error rate procedure of Benjamini and Hochberg while controlling the same false discovery rate (FDR). In this paper it is proved that when the number of alternatives is small compared to the total number of hypotheses, Storey's method can be less powerful than that of Benjamini and Hochberg. Moreover, the two procedures are compared by setting them to produce the same FDR. The difference in power between Storey's procedure and that of Benjamini and Hochberg is near zero when the distance between the null and alternative distributions is large, but Benjamini and Hochberg's procedure becomes more powerful as the distance decreases. It is shown that modifying the Benjamini and Hochberg procedure to incorporate an estimate of the proportion of true null hypotheses as proposed by Black gives a procedure with superior power.     

On the incidence–prevalence relation and length‐biased sampling

For many diseases, logistic constraints render large incidence studies difficult to carry out. This becomes a drawback, particularly when a new study is needed each time the incidence rate is investigated in a new population. By carrying out a prevalent cohort study with follow‐up it is possible to estimate the incidence rate if it is constant. The authors derive the maximum likelihood estimator (MLE) of the overall incidence rate, λ, as well as age‐specific incidence rates, by exploiting the epidemiologic relationship, (prevalence odds) = (incidence rate) × (mean duration) (P/[1 ? P] = λ × µ). The authors establish the asymptotic distributions of the MLEs and provide approximate confidence intervals for the parameters. Moreover, the MLE of λ is asymptotically most efficient and is the natural estimator obtained by substituting the marginal maximum likelihood estimators for P and µ into P/[1 ? P] = λ × µ. Following‐up the subjects allows the authors to develop these widely applicable procedures. The authors apply their methods to data collected as part of the Canadian Study of Health and Ageing to estimate the incidence rate of dementia amongst elderly Canadians. The Canadian Journal of Statistics © 2009 Statistical Society of Canada