一类高阶非线性泛函方程的振动准则

研究了变系数高阶非线性泛函方程x（g（t））=P（t）x（t）＋ m∑im1 Qi（t）x（gK＋i（t））,的解的振动性。得到了一些新的振动准则．所得蛄论推广了目前已有结果,此外,给出了新振动准则在差分方程中的一些应用．     

Inference on the ratio of two coefficients of variation of two lognormal distributions

The coefficient of variation (CV) can be used as an index of reliability of measurement. The lognormal distribution has been applied to fit data in many fields. We developed approximate interval estimation of the ratio of two coefficients of variation (CsV) for lognormal distributions by using the Wald-type, Fieller-type, log methods, and method of variance estimates recovery (MOVER). The simulation studies show that empirical coverage rates of the methods are satisfactorily close to a nominal coverage rate for medium sample sizes.     

Sensitivity Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is fraught with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 billion dollars to 3 billion dollars in losses late on the 12th to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm struck the resort areas of Charlotte Harbor and moved across the densely populated central part of the state, with early poststorm estimates in the 28 dollars to 31 billion dollars range, and final estimates converging at 15 billion dollars as the actual intensity at landfall became apparent. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has a great appreciation for the role of computer models in projecting losses from hurricanes. The FCHLPM contracts with a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a sophisticated computer model based on the Holland wind field. Sensitivity analyses presented in this article utilize standardized regression coefficients to quantify the contribution of the computer input variables to the magnitude of the wind speed.     

中国科技人力资源评价指标体系构建方法研究

通过对科技人力资源状况描述的系统分析,构建了中国科技人力资源初始评价指标体系,运用偏相关系数法和变异系数法对指标进行了筛选,并用筛选前后的指标按四个方面对31个地区进行样本聚类分析比较,说明所筛选确定的15项综合评价指标的筛选结果可靠,最终形成一套符合我国国情、科学合理的中国科技人力资源评价指标体系。     

基于单神经元的非线性单值预测控制

利用单神经元构造被控对象的预测模型,给出了基于单神经元预测模型的单值预测控制算法,证明了该算法具有结构简单、运算量小、速度快的特点.通过理论分析给出了神经元学习收敛的充分条件.仿真结果表明了该算法的可行性.     

Lower bounds for confidence coefficients for confidence intervals for finite population quantiles

Assuming stratified simple random sampling, a confidence interval for a finite population quantile may be desired. Using a confidence interval with endpoints given by order statistics from the combined stratified sample, several procedures to obtain lower bounds (and approximations for the lower bounds) for the confidence coefficients are presented. The procedures differ with respect to the amount of prior information assumed about the var-iate values in the finite population, and the extent to which sample data is used to estimate the lower bounds.     

Comparing least-squares lines for testing level changes in interrupted time-series analysis

A likelihood ratio test of equality of coefficients of variation or relative errors for two samples of unequal size is presented. The asymptotic distribution is found and the distribution is tabled for small sizes via computer simulation. Kolmogrov-Smirnov confidence intervals are constructed on the percentiles included in the table. Power studies are also simulated and the results indicate that the test has good power for small coefficients of variation     

Higher order moments of order statistics from the Lindley distribution and associated inference

ABSTRACT

The Lindley distribution is an important distribution for analysing the stress–strength reliability models and lifetime data. In many ways, the Lindley distribution is a better model than that based on the exponential distribution. Order statistics arise naturally in many of such applications. In this paper, we derive the exact explicit expressions for the single, double (product), triple and quadruple moments of order statistics from the Lindley distribution. Then, we use these moments to obtain the best linear unbiased estimates (BLUEs) of the location and scale parameters based on Type-II right-censored samples. Next, we use these results to determine the mean, variance, and coefficients of skewness and kurtosis of some certain linear functions of order statistics to develop Edgeworth approximate confidence intervals of the location and scale Lindley parameters. In addition, we carry out some numerical illustrations through Monte Carlo simulations to show the usefulness of the findings. Finally, we apply the findings of the paper to some real data set.     

Modeling the contemporaneous relationship in a continuous variable panel model

Continuous-variable panel models are widely used in social and business research to assess the relationships between variables over time given measurements at several waves on a single sample of individuals. Emphasis is often placed on estimating and testing the cross-effects which are the regression coefficients indicating the lagged effect of one variable on another. For the simple two-variable model we consider the problem of incorpomating the contemporaneous relationship between the variables into the model. Three extensions of the “independent regressions” model are considered. Their similarities and differences are examined. The use of the models is illustrated by examining data on the attitudes toward the criminal justice system and capital punishment for a panel of petit jurors.     

Efficiency of split questionnaire surveys

We consider a general design that allows information for different patterns, or sets, of data items to be collected from different sample units, which we call a Split Questionnaire Design (SQD). While SQDs have been historically used to accommodate constraints on respondent burden, this paper shows they can also be an efficient design option. The efficiency of a design can be measured by the cost required to meet constraints on the accuracy of estimates. Moreover, this paper shows how an SQD provides considerable flexibility when exploring the balance between the design's efficiency and the burden it places on respondents. The targets of interest to the design are analytic parameters, such as regression coefficients. Empirical results show that SQDs are worthwhile considering.