Optimal estimating functions and wedderburn's quasi-likelihood

There are two inference methods which can be considered as developed from the classical least squares and maximum likelihood methods. One was put forward by Wedderburn (1974) and is called the quasi-likelihood method. Another was introduced by Godambe and others from the viewpoint of the estimating functions. This method is also called quasi-likelihood although there x are some differences between these two methods. In order to clarify the relationship, this paper provides a unified discussion of the two methods from the viewpoint of estimating functions.     

On the application of statistical learning approaches to construct inverse probability weights in marginal structural Cox models: Hedging against weight-model misspecification

The marginal structural Cox model (MSCM) estimates can be highly sensitive to weight-model misspecification. We assess the performance of various popular statistical learners, such as LASSO, support vector machines, CART, bagged CART, and boosted CART, in estimating MSCM weights. When weight-models are misspecified, we find that the weights computed from boosted CART generally lead to less MSE and better coverage for the MSCM estimates. This study is motivated by the investigation of the impact of beta-interferon treatment on disability progression in subjects with multiple sclerosis from British Columbia, Canada (1995–2008).     

Saddlepoint condition on a predictor to reconfirm the need for the assumption of a prior distribution

Saddlepoint conditions on a predictor are introduced and developed to reconfirm the need for the assumption of a prior distribution in constructing a useful inferential procedure. A condition yields that the predictor induced from the maximum likelihood estimator is the worst under a loss, while the predictor induced from a suitable posterior mean is the best. This result indicates the promising role of Bayesian criteria, such as the deviance information criterion (DIC). As an implication, we critique the conventional empirical Bayes method because of its partial assumption of a prior distribution.     

朦胧诗后先锋诗歌概观

朦胧诗后先锋诗歌的历史充满反叛性,它的反叛破坏大于建设,疏离多于超越;它对意象与象征艺术的解构、日常性叙述的重视、多元技巧的综合调试,刷新了新诗的本质内涵;它的民刊策略和边缘立场,在保证先锋性同时,表明自身还存在着典型的亚文化特征。     

A bivariate generalized linear model with an application to meteorological data analysis

A bivariate generalized linear model is developed as a mixture distribution with one component of the mixture being discrete with probability mass only at the origin. The use of the proposed model is illustrated by analyzing local area meteorological measurements with constant correlation structure that incorporates predictor variables. The Monte Carlo study is performed to evaluate the inferential efficiency of model parameters for two types of true models. These results suggest that the estimates of regression parameters are consistent and the efficiency of the inference increases for the proposed model for ρ≥0.50 especially in larger samples. As an illustration of a bivariate generalized linear model, we analyze a precipitation monitoring data of adjacent local stations for Tokyo and Yokohama.     

Analysis of Circular Longitudinal Data Based on Generalized Estimating Equations

This paper derives estimating equations for modelling circular data with longitudinal structure for a family of circular distributions with two parameters. Estimating equations for modelling the circular mean and the resultant length are given separately. Estimating equations are then derived for a mixed model. This paper shows that the estimators that follow from these equations are consistent and asymptotically normal. The results are illustrated by an example about the direction taken by homing pigeons.     

The relationship between double-exponential families and extended quasi-likelihood families, with application to modelling Geissler's human sex ratio data

The human sex ratio data, collected in Saxony in the 19th century by Geissler, are reanalysed by joint modelling of the mean and dispersion. Extended quasi-likelihood and the unnormalized double-exponential family are shown to lead to identical inference. The use of the unnormalized form is discussed. The relationship between multinomial and Poisson models is studied for overdispersed data.     

Approximate likelihood methods for estimating local recombination rates

Summary. There is currently great interest in understanding the way in which recombination rates vary, over short scales, across the human genome. Aside from inherent interest, an understanding of this local variation is essential for the sensible design and analysis of many studies aimed at elucidating the genetic basis of common diseases or of human population histories. Standard pedigree-based approaches do not have the fine scale resolution that is needed to address this issue. In contrast, samples of deoxyribonucleic acid sequences from unrelated chromosomes in the population carry relevant information, but inference from such data is extremely challenging. Although there has been much recent interest in the development of full likelihood inference methods for estimating local recombination rates from such data, they are not currently practicable for data sets of the size being generated by modern experimental techniques. We introduce and study two approximate likelihood methods. The first, a marginal likelihood, ignores some of the data. A careful choice of what to ignore results in substantial computational savings with virtually no loss of relevant information. For larger sequences, we introduce a 'composite' likelihood, which approximates the model of interest by ignoring certain long-range dependences. An informal asymptotic analysis and a simulation study suggest that inference based on the composite likelihood is practicable and performs well. We combine both methods to reanalyse data from the lipoprotein lipase gene, and the results seriously question conclusions from some earlier studies of these data.     

游走的"边缘人":新时期乡族小说的新形象

游走的"边缘人"——流动农民是现代化进程中中国社会出现的新型阶层。"边缘人"的兴起是现代化和市场经济带来的必然结果,对"边缘人"的发现和书写,构成当代文学不可忽视的大事。忍让型"边缘人"经济地位的缺席预示了他们劳动价值的失范,"自我认同"型"边缘人"则通过自身的抗争努力寻求社会的认同。新时期乡族小说以特有的艺术形式反映了这些"边缘人"所表现的生存、伦理、价值和文化等方面的变化。     

中国企业的战略困惑与战略提升

国际化视野下的中国企业,由于低度化的陷阱,表现为边缘化、同构化、无序化的矛盾, 并且成为国际资本扩展的主要目标。摆脱陷阱的对策是:价值创新,集聚创新和功能创新。