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1.
Abdelbaset Abdalla 《Journal of Statistical Computation and Simulation》2019,89(14):2782-2800
Despite the popularity and importance, there is limited work on modelling data which come from complex survey design using finite mixture models. In this work, we explored the use of finite mixture regression models when the samples were drawn using a complex survey design. In particular, we considered modelling data collected based on stratified sampling design. We developed a new design-based inference where we integrated sampling weights in the complete-data log-likelihood function. The expectation–maximisation algorithm was developed accordingly. A simulation study was conducted to compare the new methodology with the usual finite mixture of a regression model. The comparison was done using bias-variance components of mean square error. Additionally, a simulation study was conducted to assess the ability of the Bayesian information criterion to select the optimal number of components under the proposed modelling approach. The methodology was implemented on real data with good results. 相似文献
2.
陈佳冀 《湖南大学学报(社会科学版)》2019,(5):87-94
对初始情境中受难者“陷困”功能的探讨,是“动物叙事”叙事语法研究中不容忽视的一环,其中贯穿了一个最为基础的叙事功能指向——“抉择之痛”。强调“动物与人”两类受难者角色在身体、心理抑或情感维度陷入某种矛盾与纠结的状态,并且彼此间时常呈现出一定的矛盾悖反性。这一角色身份由动物形象与人类形象分别或共同承担,均指向一种叙事伦理层面的现代境遇的表达。在题材范畴方面,这一功能指涉涵盖了家养类与野生类“动物叙事”各自的叙事范畴。其效力边际已不仅仅局限在单纯生态视域与人性指涉的层面,而是凸显现代语境下人类所面临的共通性的伦理困境:一种挥之不去的矛盾、困惑与不安的情感和心境的写照。 相似文献
3.
Matthias Neumann Christian Hirsch Jakub Stank Viktor Bene Volker Schmidt 《Scandinavian Journal of Statistics》2019,46(3):848-884
We investigate the problem of estimating geodesic tortuosity and constrictivity as two structural characteristics of stationary random closed sets. They are of central importance for the analysis of effective transport properties in porous or composite materials. Loosely speaking, geodesic tortuosity measures the windedness of paths, whereas the notion of constrictivity captures the appearance of bottlenecks resulting from narrow passages within a given materials phase. We first provide mathematically precise definitions of these quantities and introduce appropriate estimators. Then, we show strong consistency of these estimators for unboundedly growing sampling windows. In order to apply our estimators to real data sets, the extent of edge effects needs to be controlled. This is illustrated using a model for a multiphase material that is incorporated in solid oxide fuel cells. 相似文献
4.
AbstractWeak convergence and moment convergence issues are investigated for the New Better than Average Failure Rate (NBAFR) family (introduced by Loh (1984)). We explore the validity of these results in the context of a more general ageing class that we introduce. We prove some new properties of this class and derive its interrelationships with other non-monotonic ageing families. Reliability and moment bounds are obtained and an interesting characterization of exponentiality is proved. Special cases of our results lead to new theorems for the NBAFR class. Finally weak convergence and related issues are established for this class. 相似文献
5.
6.
沈再英 《浙江树人大学学报》2006,6(6):92-96
阅读是外语教学和学习中的重要环节。阅读不仅是读者知识积累和经验积淀的反映,而且可以构架起作者和读者之间沟通的桥梁。掌握了语篇生成的理论基础和技巧,读者就能在阅读中驾轻就熟地理解作者的意图和观点,从而达到理解语篇的目的。 相似文献
7.
在实一致光滑Banach空间中引入了一类新的逼近三个极值强伪压缩映象唯一公共不动点的带误差迭代序列,以及通过Petryshyn不等式讨论了该带误差迭代序列的收敛性. 相似文献
8.
朱玉红 《吉林师范大学学报》2002,(1):68-70
义利观问题是中国伦理思想史的核心问题之一,历代思想家都十分重视对它的研究。王夫之在总结、继承前哲义利思想的基础上,提出了自己的义利观,并对义利进行了层次性及相对性的分析,既继承了传统道义论的精华,又极大地丰富了中国古代伦理思想的内涵。 相似文献
9.
If a population contains many zero values and the sample size is not very large, the traditional normal approximation‐based confidence intervals for the population mean may have poor coverage probabilities. This problem is substantially reduced by constructing parametric likelihood ratio intervals when an appropriate mixture model can be found. In the context of survey sampling, however, there is a general preference for making minimal assumptions about the population under study. The authors have therefore investigated the coverage properties of nonparametric empirical likelihood confidence intervals for the population mean. They show that under a variety of hypothetical populations, these intervals often outperformed parametric likelihood intervals by having more balanced coverage rates and larger lower bounds. The authors illustrate their methodology using data from the Canadian Labour Force Survey for the year 2000. 相似文献
10.
Amy H. Herring Joseph G. Ibrahim Stuart R. Lipsitz 《Journal of the Royal Statistical Society. Series C, Applied statistics》2004,53(2):293-310
Summary. Non-ignorable missing data, a serious problem in both clinical trials and observational studies, can lead to biased inferences. Quality-of-life measures have become increasingly popular in clinical trials. However, these measures are often incompletely observed, and investigators may suspect that missing quality-of-life data are likely to be non-ignorable. Although several recent references have addressed missing covariates in survival analysis, they all required the assumption that missingness is at random or that all covariates are discrete. We present a method for estimating the parameters in the Cox proportional hazards model when missing covariates may be non-ignorable and continuous or discrete. Our method is useful in reducing the bias and improving efficiency in the presence of missing data. The methodology clearly specifies assumptions about the missing data mechanism and, through sensitivity analysis, helps investigators to understand the potential effect of missing data on study results. 相似文献