A bias analysis of Weibull models under heaped data

Retrospectively collected duration data are often reported incorrectly. An important type of such an error is heaping—respondents tend to round-off or round-up the data according to some rule of thumb. For two special cases of the Weibull model we study the behaviour of the ‘naive estimators’, which simply ignore the measurement error due to heaping, and derive closed expressions for the asymptotic bias. These results give a formal justification of empirical evidence and simulation-based findings reported in the literature. Additionally, situations where a remarkable bias has to be expected can be identified, and an exact bias correction can be performed.     

扫描电路的相对时差

研究了简单式、自举式、密勒式和恒流管充电式四种扫描电路的相对时差与其电源利用系数、非线性系数的关系,并且阐明了扫描电路相对时差的实用价值.     

上证50ETF的运作状况分析

本文对上证50ETF的主要运作指标跟踪误差与折溢价水平进行计算分析,并通过结合国外ETF的运作状况进行比较,得出:我国ETF的发展由于起步较晚,且股权分置改革尚未完成,对上证50ETF的运作产生一定的影响,因而与国际上著名的ETF产品的运作存在一定差距。     

硕士研究生入学面试评价方法研究

本文根据硕士研究生入学面试的要求,建立了一套硕士研究生入学面试评价指标体系,给出了各评价指标的权重系数,并提出了应用模糊综合评价方法与加法合成法相结合进行硕士研究生入学面试评分的方法。     

Estimation of the intercept parameter for linear regression model with uncertain non-sample prior information

This paper considers alternative estimators of the intercept parameter of the linear regression model with normal error when uncertain non-sample prior information about the value of the slope parameter is available. The maximum likelihood, restricted, preliminary test and shrinkage estimators are considered. Based on their quadratic biases and mean square errors the relative performances of the estimators are investigated. Both analytical and graphical comparisons are explored. None of the estimators is found to be uniformly dominating the others. However, if the non-sample prior information regarding the value of the slope is not too far from its true value, the shrinkage estimator of the intercept parameter dominates the rest of the estimators.     

一类热传导方程的H1-Galerkin混合有限元分析

采用H1 Galerkin混合有限元方法对一类热传导方程的初边值问题,提出了半离散H1 Galerkin混合有限元格式,通过误差分析,得到H1 Galerkin混合有限元解与真解的L2模和H1模的最优阶误差估计.     

时间序列的新息预报

根据实际问题，针对有限个数据ｗｋ，ｗｋ－１，…，ｗ１，给出了Ｗｋ＋ｌ的严格的线性最小方差预报和实现这种预报的适时递推公式和计算方法，并与平稳预报进行比较，得到两者有渐近相等的一步预报误差方差。     

阵列误差对多参数联合估计性能的影响

建立了频率、二维到达角和极化联合估计的阵列误差信号模型,分析了阵列误差对用ESPEIT算法进行参数估计性能的影响。推导了在阵列误差模型下,频率、二维到达角和极化联合估计算法中各参数估计结果的均方误差。计算机模拟结果证实了分析结果的正确性。     

非公有制经济发展的误区与健康发展的对策

我国非公有制经济发展存在上规模、上档次、集体化、全盘否定家族式管理的误区.文章认为要在全面认识非公有制经济发展误区的基础上,积极寻找一套行之有效的促进非公有制经济健康发展的实现方式和途径.     

Covariate Adjusted Correlation Analysis via Varying Coefficient Models

Abstract.  We propose covariate adjusted correlation (Cadcor) analysis to target the correlation between two hidden variables that are observed after being multiplied by an unknown function of a common observable confounding variable. The distorting effects of this confounding may alter the correlation relation between the hidden variables. Covariate adjusted correlation analysis enables consistent estimation of this correlation, by targeting the definition of correlation through the slopes of the regressions of the hidden variables on each other and by establishing a connection to varying-coefficient regression. The asymptotic distribution of the resulting adjusted correlation estimate is established. These distribution results, when combined with proposed consistent estimates of the asymptotic variance, lead to the construction of approximate confidence intervals and inference for adjusted correlations. We illustrate our approach through an application to the Boston house price data. Finite sample properties of the proposed procedures are investigated through a simulation study.