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81.
高正兴 《江汉大学学报(人文科学版)》1995,(6)
本文用递推数列的方法研究了一个齐次的有限Markov链(Ehrenfest模型),得出与李政道著“统计力学”相同的结论。但本文表述方式较之准确、简练,推导所用数学工具较之初等、直接。 相似文献
82.
Barbara Lee Bleau 《决策科学》1981,12(2):294-309
A Markov-chain faculty planning model to be used with institution-specific data is presented to describe and better understand the complex phenomena of faculty movement through an institution and on its relationship to salary costs, composition of the faculty, and faculty turnover rate. The model updates the earlier work done at Stanford University and Oregon State University by the addition of states for fixed-term appointments and for part-time FTEs to reflect accurately the current hiring trends at many institutions. The model is implemented and tested at two different institutions. The findings suggest that the model is a viable means of gaining useful insights and quantitative data on the faculty profile, salary costs, expected departures, and part-time trends. And further, when used as a planning tool, and the model apparently is comprehensive and flexible enough to analyze the probable effects, both in the short and long run, of alternative personnel policies on the faculty composition. 相似文献
83.
我国区域经济差距的空间演变趋势及其成因 总被引:1,自引:0,他引:1
文章采用空间马尔科夫链方法分析了我国区域差距和经济发展的空间效应及演变趋势,发现地理背景对经济类型转移具有显著影响,区域经济类型不会发生明显的跃迁,经济增长存在空间相关性和路径依赖性。然后,利用Kernel密度分布法提供了同时考察经济增长及区域差距的新分析框架,从经济增长分布演进的视角,分析了我国区域经济差距的原因。研究结果显示,中国经济差距扩散的动力来源于效率改进而非要素投入。 相似文献
84.
Nuttanan Wichitaksorn 《统计学通讯:理论与方法》2020,49(8):1801-1817
AbstractThis article proposes a new approach to analyze multiple vector autoregressive (VAR) models that render us a newly constructed matrix autoregressive (MtAR) model based on a matrix-variate normal distribution with two covariance matrices. The MtAR is a generalization of VAR models where the two covariance matrices allow the extension of MtAR to a structural MtAR analysis. The proposed MtAR can also incorporate different lag orders across VAR systems that provide more flexibility to the model. The estimation results from a simulation study and an empirical study on macroeconomic application show favorable performance of our proposed models and method. 相似文献
85.
基于Markov过程的市场预测 总被引:1,自引:0,他引:1
何龙敏 《北华大学学报(社会科学版)》1999,(5)
本文根据产品在市场流通领域中所处地位,把它分为四个状态,利用Markov过程建立其状态分布的数学模型,给企业提供市场信息,以便组织货源与作出科学决策,从而减少参与市场竞争的盲目性. 相似文献
86.
Model-based clustering for social networks 总被引:5,自引:0,他引:5
Mark S. Handcock Adrian E. Raftery Jeremy M. Tantrum 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》2007,170(2):301-354
Summary. Network models are widely used to represent relations between interacting units or actors. Network data often exhibit transitivity, meaning that two actors that have ties to a third actor are more likely to be tied than actors that do not, homophily by attributes of the actors or dyads, and clustering. Interest often focuses on finding clusters of actors or ties, and the number of groups in the data is typically unknown. We propose a new model, the latent position cluster model , under which the probability of a tie between two actors depends on the distance between them in an unobserved Euclidean 'social space', and the actors' locations in the latent social space arise from a mixture of distributions, each corresponding to a cluster. We propose two estimation methods: a two-stage maximum likelihood method and a fully Bayesian method that uses Markov chain Monte Carlo sampling. The former is quicker and simpler, but the latter performs better. We also propose a Bayesian way of determining the number of clusters that are present by using approximate conditional Bayes factors. Our model represents transitivity, homophily by attributes and clustering simultaneously and does not require the number of clusters to be known. The model makes it easy to simulate realistic networks with clustering, which are potentially useful as inputs to models of more complex systems of which the network is part, such as epidemic models of infectious disease. We apply the model to two networks of social relations. A free software package in the R statistical language, latentnet, is available to analyse data by using the model. 相似文献
87.
本文研究了一个M/PH/1排队,这个排队系统的服务台每服务完一定量的顾客,就要进行一闪检修,然后才继续服务。在检修时间服从位相(PH)分布时,本文求出了这个系统达到平衡的条件以及有关排队率和可靠性的指标。顺便求出了普通的M/PH/1系统第M个顾客离去时刻的分布。 相似文献
88.
A. K. S. Alshabani I. L. Dryden C. D. Litton J. Richardson 《Journal of the Royal Statistical Society. Series C, Applied statistics》2007,56(4):415-428
Summary. We consider the Bayesian analysis of human movement data, where the subjects perform various reaching tasks. A set of markers is placed on each subject and a system of cameras records the three-dimensional Cartesian co-ordinates of the markers during the reaching movement. It is of interest to describe the mean and variability of the curves that are traced by the markers during one reaching movement, and to identify any differences due to covariates. We propose a methodology based on a hierarchical Bayesian model for the curves. An important part of the method is to obtain identifiable features of the movement so that different curves can be compared after temporal warping. We consider four landmarks and a set of equally spaced pseudolandmarks are located in between. We demonstrate that the algorithm works well in locating the landmarks, and shape analysis techniques are used to describe the posterior distribution of the mean curve. A feature of this type of data is that some parts of the movement data may be missing—the Bayesian methodology is easily adapted to cope with this situation. 相似文献
89.
Convergence of Heavy-tailed Monte Carlo Markov Chain Algorithms 总被引:1,自引:0,他引:1
Abstract. In this paper, we use recent results of Jarner & Roberts ( Ann. Appl. Probab., 12, 2002, 224) to show polynomial convergence rates of Monte Carlo Markov Chain algorithms with polynomial target distributions, in particular random-walk Metropolis algorithms, Langevin algorithms and independence samplers. We also use similar methodology to consider polynomial convergence of the Gibbs sampler on a constrained state space. The main result for the random-walk Metropolis algorithm is that heavy-tailed proposal distributions lead to higher rates of convergence and thus to qualitatively better algorithms as measured, for instance, by the existence of central limit theorems for higher moments. Thus, the paper gives for the first time a theoretical justification for the common belief that heavy-tailed proposal distributions improve convergence in the context of random-walk Metropolis algorithms. Similar results are shown to hold for Langevin algorithms and the independence sampler, while results for the mixing of Gibbs samplers on uniform distributions on constrained spaces are rather different in character. 相似文献
90.
Semiparametric Bayesian classification with longitudinal markers 总被引:1,自引:0,他引:1
Rolando De la Cruz-Mesía Fernando A. Quintana Peter Müller 《Journal of the Royal Statistical Society. Series C, Applied statistics》2007,56(2):119-137
Summary. We analyse data from a study involving 173 pregnant women. The data are observed values of the β human chorionic gonadotropin hormone measured during the first 80 days of gestational age, including from one up to six longitudinal responses for each woman. The main objective in this study is to predict normal versus abnormal pregnancy outcomes from data that are available at the early stages of pregnancy. We achieve the desired classification with a semiparametric hierarchical model. Specifically, we consider a Dirichlet process mixture prior for the distribution of the random effects in each group. The unknown random-effects distributions are allowed to vary across groups but are made dependent by using a design vector to select different features of a single underlying random probability measure. The resulting model is an extension of the dependent Dirichlet process model, with an additional probability model for group classification. The model is shown to perform better than an alternative model which is based on independent Dirichlet processes for the groups. Relevant posterior distributions are summarized by using Markov chain Monte Carlo methods. 相似文献