Shrinkage Estimators of Intercept Parameters of Two Simple Regression Models with Suspected Equal Slopes

Estimators of the intercept parameter of a simple linear regression model involves the slope estimator. In this article, we consider the estimation of the intercept parameters of two linear regression models with normal errors, when it is a priori suspected that the two regression lines are parallel, but in doubt. We also introduce a coefficient of distrust as a measure of degree of lack of trust on the uncertain prior information regarding the equality of two slopes. Three different estimators of the intercept parameters are defined by using the sample data, the non sample uncertain prior information, an appropriate test statistic, and the coefficient of distrust. The relative performances of the unrestricted, shrinkage restricted and shrinkage preliminary test estimators are investigated based on the analyses of the bias and risk functions under quadratic loss. If the prior information is precise and the coefficient of distrust is small, the shrinkage preliminary test estimator overperforms the other estimators. An example based on a medical study is used to illustrate the method.     

面向不确定多属性决策问题的范例检索算法研究

将不确定多属性决策问题转化为不确定性多属性范例的检索问题,利用范例推理方法获取最相似范例作对目标决策问题的近似解,通过范例修正缩短该近似解与目标决策问题解之间的差距直至完全一致.文章系统地提出了适合于不确定多属性问题检索要求的范例检索算法(RA-UMDM),重点研究了范例聚类、用基于梯形模糊集和改进的欧氏距离检索算法分别解决范例中模糊概念属性、区间特征属性的相似度计算问题.将该方法应用于两家医院临床辅助诊断决策过程求得了较为准确的解,并且基于范例库对RA-UMDM法的有效性、准确度、效率等进行了实验,结果表明该方法能够满足不确定多属性决策问题的检索要求,检索速度较快、质量高.     

高等教育：观念与现实之间的问题及应对

教育目的的实现需要条件,如果条件不具备或这些条件之间的关系不匹配,都可能成为实现教育目的的障碍。针对目前高等教育教学中普遍存在的四大问题,应用以下几方面的思路去应对：价值取向上应侧重对“人”的培养;知识论上,应侧重不确定性知识;方法论上,应侧重创新性学习;评价观上应侧重对“价”的评估。     

基于区间灰色不确定语言的多准则决策方法

定义了区间灰色不确定语言及其运算法则和距离公式。拓展了连续区间数据的OWA(C-OWA)算子,提出了基于区间灰色不确定语言的有序加权C-OWA(IGULOWC-OWA)算子,并对其性质进行了分析。针对准则权重已知而方案的准则值为区间灰色不确定语言的多准则决策问题,提出了一种基于IGULOWC-OWA算子的多准则决策方法。该方法通过对各方案在各个准则下的评价值进行转换,将区间灰色不确定语言转化为不确定语言,然后,利用集结算子计算出各个方案的综合准则值,进而得出各方案的排序。最后通过算例表明了方法的可行性和有效性。     

设施失灵风险下不确定需求应急定位-路径鲁棒优化研究

为抵御突发灾害对路网造成的破坏性和设施失灵风险,降低系统成本,并快速完成应急救援任务,本文考虑到受灾点物资需求量的不确定和风险对救援系统的影响,采用直升机进行物资运送以规避路径风险。建立了最小化应急物流系统总成本和物资到达需求点总救援时间为双目标的应急物流定位-路径鲁棒优化模型,基于相对鲁棒优化方法处理需求不确定,采用偏差鲁棒优化思想描述设施失灵风险损失,采用遗传算法进行求解。通过对三个算例进行数据仿真实验,证明了相对鲁棒优化方法在处理需求不确定和偏差鲁棒优化方法在处理设施失灵风险方面的有效性,进而为解决应急设施点的开设和救援物资的安全及时准确配送,增强应急物流系统的风险应对能力提供了有效的方法。     

Uncertainty Analysis in Fault Tree Models with Dependent Basic Events

In general, two types of dependence need to be considered when estimating the probability of the top event (TE) of a fault tree (FT): “objective” dependence between the (random) occurrences of different basic events (BEs) in the FT and “state‐of‐knowledge” (epistemic) dependence between estimates of the epistemically uncertain probabilities of some BEs of the FT model. In this article, we study the effects on the TE probability of objective and epistemic dependences. The well‐known Frèchet bounds and the distribution envelope determination (DEnv) method are used to model all kinds of (possibly unknown) objective and epistemic dependences, respectively. For exemplification, the analyses are carried out on a FT with six BEs. Results show that both types of dependence significantly affect the TE probability; however, the effects of epistemic dependence are likely to be overwhelmed by those of objective dependence (if present).     

线性二层决策问题的期望收益模型及算法

下层反应不唯一时 ,如何确定二层线性决策问题最优策略为一非确定型决策问题 .对此类问题 ,本文通过引入领导者对追随者合作程度的期望系数 ,提出期望收益模型 .利用双罚函数把该问题转换为一单层次优化问题 ,并提出一种求解问题的全局优化算法 .应用此模型分析二层线性问题可知 :对存在不确定性反应的二层决策问题 ,下层追随者与上层领导者的合作态度是领导者确定其最优策略的关键 ;对下层追随者而言 ,某些情况下 ,采取与领导者部分合作的态度对其自身收益的提高是合理的     

俄汉语大约数量意义的表达形式和手段对比

数量意义属逻辑、语言学范畴,是客观事物在人们头脑中的反映,是经过人们概括、抽象而产生的某一类事物在数量上的共同特征。从俄汉对比角度研究数量意义中的一种——大约数量意义,目的在于揭示其相异和相同之处。本文遵循从意义到形式,从俄语到汉语的原则,通过大量的例证,对比俄汉语大约数量意义的表达手段,揭示俄汉语大约数量结构构成规律和语义差别,解决俄汉语教学中学生在翻译此类问题时的模糊认识,具有较强的实践价值。     

Improved estimation of the mean vector for student-t model

Improved James-Stein type estimation of the mean vector μ of a multovaroate Student-t population of dimension p with ν degrees of freedom is considered. In addition to the sample data, uncertain prior information on the value of the mean vector, in the form of a null hypothesis, is used for the estiamtion. The usual maximum liklihood estimator((mle) of μ is obtained and a test statistic for testing H₀:μ=μ₀ is derived. Based on the mle of μ and the tes statistic the preliminary test estimator (PTE), Stein-type shrinkage estimator (SE) and positive-rule shrinkage esiimator (PRSE) are defined. The bias and the quadratic risk of the estimators are evaiuated. The relative performances of the estimators are mvestigated by analyzing the risks under different condltlons It is observed that the FRSE dommates over he other three estimators, regardless of the vaiidity of the null hypothesis and the value ν.     

基于不确定语言变量的风险投资项目群体评价方法的研究

在风险投资运作过程中,对项目的风险评估是其关键环节.由于影响风险评估项目的因素具有不确定性,本文引入不确定语言变量的运算法则.先使用不确定语言加权平均算子对信息进行集结,针对属性权重完全未知的情形,给出一个求解权重的方法;再通过不确定语言加权平均(ULWA)算子,对不确定语言决策信息进行加权集成,利用已有的可能度矩阵排序公式得到决策方案的排序;最后给出实例分析,以说明该方法的有效性和可操作性.