Fitting Variance Components Model and Fixed Effects Model for One-Way Analysis of Variance to Complex Survey Data

Under complex survey sampling, in particular when selection probabilities depend on the response variable (informative sampling), the sample and population distributions are different, possibly resulting in selection bias. This article is concerned with this problem by fitting two statistical models, namely: the variance components model (a two-stage model) and the fixed effects model (a single-stage model) for one-way analysis of variance, under complex survey design, for example, two-stage sampling, stratification, and unequal probability of selection, etc. Classical theory underlying the use of the two-stage model involves simple random sampling for each of the two stages. In such cases the model in the sample, after sample selection, is the same as model for the population; before sample selection. When the selection probabilities are related to the values of the response variable, standard estimates of the population model parameters may be severely biased, leading possibly to false inference. The idea behind the approach is to extract the model holding for the sample data as a function of the model in the population and of the first order inclusion probabilities. And then fit the sample model, using analysis of variance, maximum likelihood, and pseudo maximum likelihood methods of estimation. The main feature of the proposed techniques is related to their behavior in terms of the informativeness parameter. We also show that the use of the population model that ignores the informative sampling design, yields biased model fitting.     

On proportional hazards assumption under the random effects models

The proportional hazards mixed-effects model (PHMM) was proposed to handle dependent survival data. Motivated by its application in genetic epidemiology, we study the interpretation of its parameter estimates under violations of the proportional hazards assumption. The estimated fixed effect turns out to be an averaged regression effect over time, while the estimated variance component could be unaffected, inflated or attenuated depending on whether the random effect is on the baseline hazard, and whether the non-proportional regression effect decreases or increases over time. Using the conditional distribution of the covariates we define the standardized covariate residuals, which can be used to check the proportional hazards assumption. The model checking technique is illustrated on a multi-center lung cancer trial.     

受贿罪中“为他人谋取利益”之要件探讨

在受贿罪中,“为他人谋取利益”作为其主观要件或是客观要件都不合适。受贿罪侵犯的客体是国家工作人员职务行为的廉洁性,司法实践中表现为公职行为的不可收买性。国家工作人员因职务行为索取或收受他人贿赂的,即构成受贿罪。“为他人谋取利益”不应当作为受贿罪的构成要件,但是可以作为受贿罪的量刑情节。     

On bootstrapping the number of components in finite mixtures of Poisson distributions

Finite mixture models arise in a natural way in that they are modeling unobserved population heterogeneity. It is assumed that the population consists of an unknown number k of subpopulations with parameters λ₁, ..., λ_k receiving weights p₁, ..., p_k. Because of the irregularity of the parameter space, the log-likelihood-ratio statistic (LRS) does not have a (χ²) limit distribution and therefore it is difficult to use the LRS to test for the number of components. These problems are circumvented by using the nonparametric bootstrap such that the mixture algorithm is applied B times to bootstrap samples obtained from the original sample with replacement. The number of components k is obtained as the mode of the bootstrap distribution of k. This approach is presented using the Times newspaper data and investigated in a simulation study for mixtures of Poisson data.     

地理信息系统发展趋势及展望

介绍了地理信息系统（GIS）的发展趋势,包括从单机模式向网络模式GIS、从二维向三维甚至高维、从封闭系统到开放系统、从1S到3S甚至多S集成,最终是虚拟现实到数字地球,展望了未来GIS网络化、社会化、全球化、大众化的发展方向。     

深圳特区模式和发展的思考

经济模式,是关系一个国家(地区)经济结构、经济发展方向和前景的重要理论和实践问题。深圳特区应采取什么模式?作者从不同角度,不同层面就几年来在这方面的争论,提出自己的见解。深圳特区第二个十年如何发展,作者提出关键是提高外向型经济的质素和经济效益,以及由此应该采取的几项措施。     

Requiring Connectivity in the Set Covering Problem

Given a bipartite graph with bipartition V and W, a cover is a subset C V such that each node of W is adjacent to at least one node in C. The set covering problem seeks a minimum cardinality cover. Set covering has many practical applications. In the context of reserve selection for conservation of species, V is a set of candidate sites from a reserve network, W is the set of species to be protected, and the edges describe which species are represented in each site. Some covers however may assume spatial configurations which are not adequate for conservational purposes. Indeed, for sustainability reasons the fragmentation of existing natural habitats should be avoided, since this is recognized as being disruptive to the species adapted to the habitats. Thus, connectivity appears to be an important issue for protection of biological diversity. We therefore consider along with the bipartite graph, a graph G with node set V, describing the adjacencies of the elements of V, and we look for those covers C V for which the subgraph of G induced by C is connected. We call such covers connected covers. In this paper we introduce and study some valid inequalities for the convex hull of the set of incidence vectors of connected covers.MSC2000: 90C10, 90C57This authors research was financially supported by the Portuguese Foundation for Science and Technology (FCT).This paper is part of this authors Ph.D. research.     

解读：“一本四主”课堂教学法

"一本四主"课堂教学法即以"发展为本、师生主体、问题主线、思维主轴、认知主导"为指导思想的一种现代课堂教学理论.这是一种让课堂充满生命活力的教学理论.我们从"一本四主"课堂教学法的含义、结构、理论依据、原则体系、教学策略、教学模式和评价理念与体系等方面对这一理论进行探讨.     

西部地区产业结构转换能力比较的实证研究

产业结构的演进和转换是经济发展的本质特征,也是促进经济持续稳定协调发展的关键.西部地区产业结构转换能力的地区差异十分明显,本文阐述了影响地区产业结构转换的一般因素,并通过主成分分析方法对影响西部地区产业结构转换的主要因素进行了分析,并对西部各地区产业结构转换能力、转换速度以及转换方向进行了分析评价.