Estimation of Dynamic Bivariate Mixture Models

This note compares a Bayesian Markov chain Monte Carlo approach implemented by Watanabe with a maximum likelihood ML approach based on an efficient importance sampling procedure to estimate dynamic bivariate mixture models. In these models, stock price volatility and trading volume are jointly directed by the unobservable number of price-relevant information arrivals, which is specified as a serially correlated random variable. It is shown that the efficient importance sampling technique is extremely accurate and that it produces results that differ significantly from those reported by Watanabe.     

The Estimation of Dynamic Bivariate Mixture Models

Watanabe estimated the dynamic bivariate mixture models introduced by Tauchen and Pitts and modified by Andersen using a Bayesian method via Markov chain Monte Carlo techniques. Based on a maximum likelihood method via efficient importance sampling, Liesenfeld and Richard obtained estimates that are significantly different from those of Watanabe. This note corrects the error in the multimove sampler used by Watanabe and reproduces all analyses in the work of Watanabe using a corrected multimove sampler. The estimates using the correct multimove sampler are found to be close to those obtained by Liesenfeld and Richard.     

Bayesian inference for circular distributions with unknown normalising constants

Very often, the likelihoods for circular data sets are of quite complicated forms, and the functional forms of the normalising constants, which depend upon the unknown parameters, are unknown. This latter problem generally precludes rigorous, exact inference (both classical and Bayesian) for circular data.Noting the paucity of literature on Bayesian circular data analysis, and also because realistic data analysis is naturally permitted by the Bayesian paradigm, we address the above problem taking a Bayesian perspective. In particular, we propose a methodology that combines importance sampling and Markov chain Monte Carlo (MCMC) in a very effective manner to sample from the posterior distribution of the parameters, given the circular data. With simulation study and real data analysis, we demonstrate the considerable reliability and flexibility of our proposed methodology in analysing circular data.     

Binary probability maps using a hidden conditional autoregressive Gaussian process with an application to Finnish common toad data

The Finnish common toad data of Heikkinen and Hogmander are reanalysed using an alternative fully Bayesian model that does not require a pseudolikelihood approximation and an alternative prior distribution for the true presence or absence status of toads in each 10 km×10 km square. Markov chain Monte Carlo methods are used to obtain posterior probability estimates of the square-specific presences of the common toad and these are presented as a map. The results are different from those of Heikkinen and Hogmander and we offer an explanation in terms of the prior used for square-specific presence of the toads. We suggest that our approach is more faithful to the data and avoids unnecessary confounding of effects. We demonstrate how to extend our model efficiently with square-specific covariates and illustrate this by introducing deterministic spatial changes.     

对“物流管理”和“供应链管理”的辨析

20世纪70年代末,"物流管理"传入中国;90年代末,"供应链管理"被引进到中国.物流管理作为现代供应链管理思想的起源,与传统的物流管理有着很大的区别.当前,社会各界、不同学者对物流管理与供应链管理概念的理解和所指的范围看法不一,因此,了解物流管理和供应链管理的形成和发展,国际、国内对物流及供应链的定义,物流管理及供应链管理的定义,对于区别物流管理与供应链管理的关系有一定的指导意义.     

供应链中的协作问题研究

供应链协作是供应链管理的关键。本文主要介绍了目前供应链协作问题研究的现状 ,重点从博弈论的观点讨论了供应链成员间的协作 ,并从协作策略、协作的技术方法等方面总结归纳并探讨了研究的方法和模型。     

沉重的无奈 痛苦的困惑－《无根令》文化解读

<无根令>影响颇大,作者努力挖掘传统文化积淀于世俗生活深处的种种痼疾.根链和贵贱等级症影响着当下人的生存观念和思维模式.文本呈现着一种痛苦抉择与游曳不定的艺术状态和文化张力.     

基于排队论的业务流程重组绩效分析方法

竞争的激烈化和顾客需求的多样化迫使企业从根本上重新思考企业过程重组。企业过程重组(BPR)的原则之一是横向集成活动。但是横向集成活动究竟有没有提高企业的绩效,这是个值得研究的问题。本文运用排队论的数学模型,研究活动合并对企业流程绩效之一——成本的影响,详细地讨论了活动的成本要素,比较了重组前后成本的变化。     

非奇H矩阵判别条件的推广

应用不可约矩阵的特性研究非奇H矩阵,得到了不可约矩阵是非奇H矩阵的实用判据。利用具非零元素链矩阵的性质得到其为非奇H矩阵的实用判据。所得结果不要求矩阵的对角占优条件,适用范围广,可作为非奇H矩阵的实用充分条件。     

河南省冷链物流发展现状分析

河南省是农业大省,农产品资源丰富,但是冷链物流发展尚不完善。分析河南省发展冷链物流的背景和意义,指出河南省冷链物流的优势,探寻其发展中存在的问题并给出一些解决对策,对发展冷链物流有一定的意义。