线性模型参数β的均匀压缩估计

对一般线性模型中参数β的最小二乘估计和岭估计进行了修正;把岭估计中各分量的非均匀压缩修为均匀压缩,从而得到了β的一种均匀压缩估计＾βａ,并给出了具体的求法和适用范围     

常系数齐次线性微分方程组与其相应的差分方程组之间的联系

给出了求解常系数线性齐次微分方程组和常系数线性齐次差分方程组的一个方法,指出了这两种方程组之间存在的一个有趣关系．     

A Multivariate Model for Repeated Failure Time Measurements

A parametric multivariate failure time distribution is derived from a frailty-type model with a particular frailty distribution. It covers as special cases certain distributions which have been used for multivariate survival data in recent years. Some properties of the distribution are derived: its marginal and conditional distributions lie within the parametric family, and association between the component variates can be positive or, to a limited extent, negative. The simple closed form of the survivor function is useful for right-censored data, as occur commonly in survival analysis, and for calculating uniform residuals. Also featured is the distribution of ratios of paired failure times. The model is applied to data from the literature     

无金属基底吸波结构对TE波的反射

详细分析了ＴＥ极化波以大角度入射到无金属基底的平面多层吸波结构上时的反射特性,导出连接层间电磁场的通用矩阵公式,计算了两层和三层吸波结构的反射系数,并证明了在何种条件下可以获得低的反射率,在此基础上提出了一个简易设计方法。对进气道和进气道内吸波导流板的两层和三层材料设计都获得了良好的特性。     

基于可变参数优化的相关证据合成方法研究

总结了相关证据合成的理论方法,分析了已有合成方法的不足,对相关证据的相关焦元 的分布情况进行了分析,提出一种面向问题的基于可变参数的相关证据的合成方法. 方法只对 相关焦元的基本可信数进行修正,克服了对相关证据所有焦元进行修正的弱点,使修正的对象 更加合理,修正系数可用基于学习的寻优方法得到. 在相关证据的相关焦元的基本可信数未知 的情况下也可进行相关证据的合成. 计算结果表明该方法对合成的结果有明显的改进     

On the Effect of Probability Distributions of Input Variables in Public Health Risk Assessment

A central part of probabilistic public health risk assessment is the selection of probability distributions for the uncertain input variables. In this paper, we apply the first-order reliability method (FORM)^(1–3) as a probabilistic tool to assess the effect of probability distributions of the input random variables on the probability that risk exceeds a threshold level (termed the probability of failure) and on the relevant probabilistic sensitivities. The analysis was applied to a case study given by Thompson et al. ⁽⁴⁾ on cancer risk caused by the ingestion of benzene contaminated soil. Normal, lognormal, and uniform distributions were used in the analysis. The results show that the selection of a probability distribution function for the uncertain variables in this case study had a moderate impact on the probability that values would fall above a given threshold risk when the threshold risk is at the 50th percentile of the original distribution given by Thompson et al. ⁽⁴⁾ The impact was much greater when the threshold risk level was at the 95th percentile. The impact on uncertainty sensitivity, however, showed a reversed trend, where the impact was more appreciable for the 50th percentile of the original distribution of risk given by Thompson et al. ⁴ than for the 95th percentile. Nevertheless, the choice of distribution shape did not alter the order of probabilistic sensitivity of the basic uncertain variables.     

人力资源个体价值计量方法——当期实现价值系数法

由于人力资源自身具有复杂性、不确定性的特点,使得人力资源价值难以计量。而准确的计量人力资源价值,尤其是人力资源的个体价值是人力资源会计能否实施的关键因素。针对这个问题,本文在分析前人成果的基础上提出了人力资源当期实现价值系数法计量模型。并通过实例验证了计量模型的实用性。     

论领导权结构、企业避税与会计信息可靠性的关系

以我国2013—2015年沪深两市A股类上市公司为样本,运用相关性分析和回归分析,以消除应计利润影响后的会计—税收差异作为衡量企业避税指标,用盈余激进度衡量会计信息可靠性,分析企业避税程度与会计信息可靠性的关系,并进行了稳健性检验。结果表明,企业避税程度对会计信息可靠性起负面作用。在此基础上,进一步梳理了领导权结构、企业避税与会计信息可靠性的关系,研究发现,相比两职合一的公司,企业避税程度对会计信息可靠性的负面作用主要体现在两职分离的公司。这对于深入研究企业避税与会计信息可靠性的关系具有一定的借鉴意义,可为完善公司治理机制、提高会计信息可靠性提供一定的思路借鉴和决策参考。     

Improving Risk Management: From Lame Excuses to Principled Practice

The three classic pillars of risk analysis are risk assessment (how big is the risk and how sure can we be?), risk management (what shall we do about it?), and risk communication (what shall we say about it, to whom, when, and how?). We propose two complements as important parts of these three bases: risk attribution (who or what addressable conditions actually caused an accident or loss?) and learning from experience about risk reduction (what works, and how well?). Failures in complex systems usually evoke blame, often with insufficient attention to root causes of failure, including some aspects of the situation, design decisions, or social norms and culture. Focusing on blame, however, can inhibit effective learning, instead eliciting excuses to deflect attention and perceived culpability. Productive understanding of what went wrong, and how to do better, thus requires moving past recrimination and excuses. This article identifies common blame‐shifting “lame excuses” for poor risk management. These generally contribute little to effective improvements and may leave real risks and preventable causes unaddressed. We propose principles from risk and decision sciences and organizational design to improve results. These start with organizational leadership. More specifically, they include: deliberate testing and learning—especially from near‐misses and accident precursors; careful causal analysis of accidents; risk quantification; candid expression of uncertainties about costs and benefits of risk‐reduction options; optimization of tradeoffs between gathering additional information and immediate action; promotion of safety culture; and mindful allocation of people, responsibilities, and resources to reduce risks. We propose that these principles provide sound foundations for improving successful risk management.     

Testing the Equality of Two Exponential Distributions

This paper proposes an overlapping-based test statistic for testing the equality of two exponential distributions with different scale and location parameters. The test statistic is defined as the maximum likelihood estimate of the Weitzman's overlapping coefficient, which estimates the agreement of two densities. The proposed test statistic is derived in closed form. Simulated critical points are generated for the proposed test statistic for various sample sizes and significance levels via Monte Carlo Simulations. Statistical powers of the proposed test are computed via simulation studies and compared to those of the existing Log likelihood ratio test.