On the Convergence of the Monte Carlo Maximum Likelihood Method for Latent Variable Models

While much used in practice, latent variable models raise challenging estimation problems due to the intractability of their likelihood. Monte Carlo maximum likelihood (MCML), as proposed by Geyer & Thompson (1992 ), is a simulation-based approach to maximum likelihood approximation applicable to general latent variable models. MCML can be described as an importance sampling method in which the likelihood ratio is approximated by Monte Carlo averages of importance ratios simulated from the complete data model corresponding to an arbitrary value of the unknown parameter. This paper studies the asymptotic (in the number of observations) performance of the MCML method in the case of latent variable models with independent observations. This is in contrast with previous works on the same topic which only considered conditional convergence to the maximum likelihood estimator, for a fixed set of observations. A first important result is that when is fixed, the MCML method can only be consistent if the number of simulations grows exponentially fast with the number of observations. If on the other hand, is obtained from a consistent sequence of estimates of the unknown parameter, then the requirements on the number of simulations are shown to be much weaker.     

身体素质与跳远技术教学模型建立初探

用数学量化的方法 ,分析处理有关数据 ,建构模型。利用模型指导教师在跳远教学中如何处理素质与技术的关系 ,从而使跳远教学具有较科学、量化的评价体系和理论依据。     

从动词词义看双宾语构块式和与格构块式

本文从构块式语法的角度观察双宾语结构和与格结构间构块式意义的差异。用磁体构造模型,结合BROWN语料库统计数值,来阐释双及物动词词义类型与两种构块式选用的关联性,以便准确掌握选用两种构块式的规律。     

钢纤维混凝土基本性能试验研究

通过对30个立方体试块抗压强度试验,分析了钢纤维对普通混凝土的增强作用;通过对30个小梁试件三分点加载抗折试验,研究了体积率对钢纤维混凝土(SFRC)荷载-挠度关系及荷载-极限应变关系的影响.在脆性基体中掺入钢纤维,有效地提高了复合材料承受荷载时阻止裂缝引发与扩展的能力,达到对混凝土的增强效果,尤其是对于抗折强度的增强作用,使混凝土的破坏形式由脆性破坏变为塑性破坏.     

以人为本的科技管理模式与构建

运用人本管理理论,在分析目前高校科技管理存在问题基础上,探析了知识经济时代以人为本的科技管理的内容与模式,包括中心型、激励型、机制型、多赢型的人本管理模式,并据此提出了一系列构建措施。     

大众与狂欢

狂欢是大众文化的一种重要的接受模式。它与以往的文化接受模式有所不同。但这种狂欢模式并不是大众文化时代独有的 ,其所以在大众文化时代再度兴起 ,有着时代的、审美的、心理的、社会的原因。这是一种不容忽视但需加以引导的模式。在一个多元文化的时代 ,没有或仅有这种模式都是不正常的。     

政府化行为·社会化组织·市场化运作--德国国防工业管理与军备采购模式的分析

本文在概述二战后德国国防战略方针的转变和介绍其国防工业管理与军备采购的现行机构与政策之同时 ,重点阐述并归纳总结出德国国防工业管理与军备采购模式科学与有效运行的三项内因 :政府化行为、社会化组织、市场化运作。     

大学排序行为模式不规范性及其负面影响

当代大学选优排序已成为社会参与高等教育管理、促进大学竞争与发展的重要途径。但是 ,目前社会流行的不规范的选优排序活动已经在高校和社会产生了误导和不良影响。对此进行了分析 ,并提出整顿与规范大学选优排序的几点意见。     

关于新形势下推进素质教育的几点认识

随着知识经济和信息时代的到来 ,全面推进素质教育 ,努力培养高素质创新人才在我国显得尤为迫切。素质教育的实施涉及到深刻的教育改革 ,广大教育工作者应改变教育观念 ,走出传统教育的误区 ,建立“以学生为主体 ,以创造性教育为本位”的新型教学模式 ,尽快适应新形势下素质教育的要求     

Bayesian modelling of catch in a north-west Atlantic fishery

Summary. We model daily catches of fishing boats in the Grand Bank fishing grounds. We use data on catches per species for a number of vessels collected by the European Union in the context of the Northwest Atlantic Fisheries Organization. Many variables can be thought to influence the amount caught: a number of ship characteristics (such as the size of the ship, the fishing technique used and the mesh size of the nets) are obvious candidates, but one can also consider the season or the actual location of the catch. Our database leads to 28 possible regressors (arising from six continuous variables and four categorical variables, whose 22 levels are treated separately), resulting in a set of 177 million possible linear regression models for the log-catch. Zero observations are modelled separately through a probit model. Inference is based on Bayesian model averaging, using a Markov chain Monte Carlo approach. Particular attention is paid to the prediction of catches for single and aggregated ships.