Comparing several experimental groups with a control in the multivariate case

This paper presents a multivariate extension of Dunnett's test for comparing simultaneously k treatment group means with a single control group mean. A test based on Hotelling T²statistics is presented and approximate critical values are evaluated for the case of equal numbers of observations in each group, for the .05 and .01 levels of significance, for 1 to 5 variates, for 1 to 10 treatment groups, and for varying degrees of freedom. The accuracy of the procedure for generating approximate critical values is assessed via simulation studies conducted for selected cases and an example is presented using real data.     

基于单片机AT89C51的全自动变频恒压供水系统

介绍了一种新型的变频恒压供水系统.该系统根据供水管网的用水情况,调整水泵投入台数及转速,实行全自动恒压供水,达到高效节能的目的;其水泵用变频器软启动,对电网无冲击,能延长水泵的使用寿命.     

Interval estimation in discriminant analysis for large dimension

This paper is concerned with the interval estimation for the log odds of the posterior probability that the observation vector belongs to one of two homoscedastic multivariate normal distributions (Π₁ and Π₂). We give the limiting distribution of the unbiased estimator for the log odds as the sample sizes and the dimension jointly tend to infinity, and approximate the confidence interval based on the asymptotic distribution. Small-scale simulations are performed to check the precision of the approximation.     

中国黄金市场的风险价值研究

受美国次贷危机以及中国股市低进的影响，对于中国的投资者而言，黄金作为硬通货自然就成为一种很好的实现财富保值增值的投资工具。本文以基于广义误差分布的EGARCH（1，1）模型估计了中国黄金市场的日对数回报VaR值，通过后验测试与统计分析，得出以下结论：EGARCH（1，1）模型（1）能较好地拟合黄金价格的走势（2）杜宾-沃特森（D．W）统计量为1．994103极为接近2，这意味着回报序列的自相关很弱，因此均值方程可以不考虑自回归项。     

Trade-off between quoted lead time and price

In a make-to-order environment, lead time and price can play a crucial role in determining the financial success of a firm. Their importance increases when demand is sensitive to the quoted lead time and price. A model is presented which uses the quoted lead time and price as a mechanism to determine the optimal demand level. The relationships between the model parameters and their impacts on the firm's profit is also analysed. In addition, the effect of the number of job requests, and the mean processing time are examined. Based on the results presented in this paper, there is clear indication that the firm's profit is sensitive to the inventory holding rate, and that the inventory holding cost component is redundant in the presence of a tardiness cost component.     

A Comparison of Survival Function Estimators in the Koziol–Green Model

In this paper, three competing survival function estimators are compared under the assumptions of the so-called Koziol– Green model, which is a simple model of informative random censoring. It is shown that the model specific estimators of Ebrahimi and Abdushukurov, Cheng, and Lin are asymptotically equivalent. Further, exact expressions for the (noncentral) moments of these estimators are given, and their biases are analytically compared with the bias of the familiar Kaplan–Meier estimator. Finally, MSE comparisons of the three estimators are given for some selected rates of censoring.     

The robustness of the systemwise breusch-godfrey autocorrelation test for non-normal distributed error terms

Using Monte Carlo methods, the properties of systemwise generalisations of the Breusch-Godfrey test for autocorrelated errors are studied in situations when the error terms follow either normal or non-normal distributions, and when these errors follow either AR(1) or MA(1) processes. Edgerton and Shukur (1999) studied the properties of the test using normally distributed error terms and when these errors follow an AR(1) process. When the errors follow a non-normal distribution, the performances of the tests deteriorate especially when the tails are very heavy. The performances of the tests become better (as in the case when the errors are generated by the normal distribution) when the errors are less heavy tailed.     

SoC软硬件协同技术的FPGA芯片测试新方法

针对传统的基于纯硬件平台的FPGA芯片测试方法所存在的种种问题,提出并验证了一种基于软硬件协同技术的FPGA芯片测试方法。该方法引入了软件的灵活性与可观测性等软件技术优势,具有存储深度大、可测I/O管脚数目多、自动完成配置下载(不需人工干预)和自动定位FPGA中的错误等优点,提高了FPGA的测试速度和可靠性,并降低了测试成本,与传统的自动测试仪(ATE)相比有较高的性价比。采用软硬件协同方式针对Xilinx4010的I/O单元进行了测试,实现了对FPGA芯片的自动反复配置、测试和错误定位。     

Estimation with right‐censored observations under a semi‐Markov model

The semi‐Markov process often provides a better framework than the classical Markov process for the analysis of events with multiple states. The purpose of this paper is twofold. First, we show that in the presence of right censoring, when the right end‐point of the support of the censoring time is strictly less than the right end‐point of the support of the semi‐Markov kernel, the transition probability of the semi‐Markov process is nonidentifiable, and the estimators proposed in the literature are inconsistent in general. We derive the set of all attainable values for the transition probability based on the censored data, and we propose a nonparametric inference procedure for the transition probability using this set. Second, the conventional approach to constructing confidence bands is not applicable for the semi‐Markov kernel and the sojourn time distribution. We propose new perturbation resampling methods to construct these confidence bands. Different weights and transformations are explored in the construction. We use simulation to examine our proposals and illustrate them with hospitalization data from a recent cancer survivor study. The Canadian Journal of Statistics 41: 237–256; 2013 © 2013 Statistical Society of Canada