On Bartlett correctability of empirical likelihood in generalized power divergence family

Baggerly (1998) showed that empirical likelihood is the only member in the Cressie–Read power divergence family to be Bartlett correctable. This paper strengthens Baggerly’s result by showing that in a generalized class of the power divergence family, which includes the Cressie–Read family and other nonparametric likelihood such as Schennach’s (2005, 2007) exponentially tilted empirical likelihood, empirical likelihood is still the only member to be Bartlett correctable.     

Practical approaches to principal component analysis for simultaneously dealing with missing and censored elements in chemical data

Multivariate chemical data often contain elements that are missing completely at random and the so-called left-censored elements whose values are only known to be below a definite threshold value (reporting limit). In the last several years, attention has been paid to developing methods for dealing with data containing missing elements and those that can handle data with missing elements and outliers. However, processing data with both missing and left-censored elements is still an ongoing problem.     

基于最大长度区间的区间权重向量标准化方法

区间权重向量在不确定多准则决策分析和AHP中都发挥重要作用,鉴于区间权重向量的不确定性,区间权重向量的标准化问题成为研究的一个热点.在相关研究的基础上,提出基于最大长度区间的区间权重向量标准化方法.首先为了更好理解标准化权重向量,给出标准化区间权重向量的一个等价命题;其次,提出简便的标准化区间权重向量的判定方法,并提出不同情形下,通过调整最大长度区间的区间权重向量的标准化方法;最后,通过算例及与其他方法的对比,说明该方法是简便有效的.     

On Convergence of Convex Minorant Algorithms for Distribution Estimation with Interval-Censored Data

Abstract

Local convergence results of the convex minorant (CM) algorithm to obtain the nonparametric maximum-likelihood estimator of a distribution under interval-censored observations are given. We also provide a variation of the CM algorithm, which yields global convergence. The algorithm is illustrated with data on AIDS survival time in 92 members of the U.S. Air Force.     

Pontryagin maximum principle for fractional ordinary optimal control problems

In the paper, fractional systems with Riemann–Liouville derivatives are studied. A theorem on the existence and uniqueness of a solution of a fractional ordinary Cauchy problem is given. Next, the Pontryagin maximum principle for nonlinear fractional control systems with a nonlinear integral performance index is proved. Copyright © 2013 John Wiley & Sons, Ltd.     

优先序约束的排序问题：基于最大匹配的近似算法

本文研究具有加工次序约束的单位工件开放作业和流水作业排序问题，目标函数为极小化工件最大完工时间。工件之间的加工次序约束关系可以用一个被称为优先图的有向无圈图来刻画。当机器数作为输入时，两类问题在一般优先图上都是强NP-困难的，而在入树的优先图上都是可解的。我们利用工件之间的许可对数获得了问题的新下界，并基于许可工件之间的最大匹配设计近似算法，其中匹配的许可工件对均能同时在不同机器上加工。对于一般优先图的开放作业问题和脊柱型优先图的流水作业问题，我们在理论上证明了算法的近似比为$2-\frac 2m$，其中$m$是机器数目。     

基于混合患病兄弟对IBD数据的连锁分析

患病兄弟对(affected sib-pair,ASP)设计在遗传统计中有着广泛的应用,这种设计针对的是完全兄弟对(full-sib),而在实际问题中,被抽样的患病兄弟对中常会混有一定数目的半兄弟对(half-sib).论文对这种基于IBD信息的混有半兄弟对NASP(称为mixed affected sib-pair,...     

超声散斑数字相关法应用于体面内转动测量的研究

在激光数字散斑相关法测量理论的基础上,阐述了超声散斑相关法测量的基本原理,并建立了相应的超声散斑数字相关实验分析系统。在实验分析时,首先应用模拟测量的方法对刚体面内转动对散斑场相关性的影响进行了分析;然后应用实验测量的方法再对此进行了分析;最后对刚体未知面内转角进行了实测。实验结果表明,刚体面内转动可测量的最大转角为9°,当转动角度为10°时,误差大于9%。实验中分别应用了爬山搜索法和相关系数拟合法来分别搜索整像素的位移和亚像素的位移。     

Estimation of boundary values and identification of boundary type for numerical models of aquifer flow

Inverse methods which focus on aquifer properties implicitly assume that boundary conditions are known with certainty and can therefore lead to biased results. An inverse procedure is described which allows the simultaneous estimation of not only spatially varying aquifer storage coefficients and transmissivities, but also model parameters which represent both boundary type and boundary values. The weighted least-squares procedure is based on either Bayesian or maximum likelihood arguments and requires both measurements of transient piezometric heads and prior information on all model parameters. Prior estimates and their covariance can be nonconditioned (e.g. a stationary mean and covariance structure) or conditioned on direct measurements (e.g. a kriged transmissivity field with its estimation covariance). Hypothetical examples are presented using an unsteady finite element model. In some cases, with weak prior information on the boundary type, it is possible to distinguish between prescribed head, prescribed flux and mixed boundaries. Simultaneous estimates of aquifer properties and boundary values are always possible, although their accuracy depends on the relative magnitudes of model sensitivities and prior information.     

侧向压力对岩块极限承载能力的影响研究

工程岩体宏观力学参数特别是极限承载能力的研究是岩石力学最基本、也是最困难的研究课题之一。本文采用数值模拟方法研究了侧向压力对岩块极限承载能力的影响,得到了侧向压力与极限承载能力之间的函数关系,同时还找出了岩块声发射随着侧向压力的变化规律,这些问题的解决对于用数值模拟方法研究岩体工程的宏观力学性能无疑是很有意义的。