基于马尔可夫链的产品市场保有量预测模型

售后服务机构为了准确地准备库存,都需要预测产品的市场保有量。基于马尔可夫链建立的状态概率矩阵模型,与抽样调查、时间序列法、回归分析法等方法相比,更能准确预测市场产品保有量。与传统产品相比较,更新换代速度快的电子产品,要预测其市场保有量,更需要利用状态概率矩阵模型。     

Estimating rating transition probabilites with missing data

In this article we provide a rigorous treatment of one of the central statistical issues of credit risk management. GivenK-1 rating categories, the rating of a corporate bond over a certain horizon may either stay the same or change to one of the remainingK-2 categories; in addition, it is usually the case that the rating of some bonds is withdrawn during the time interval considered in the analysis. When estimating transition probabilities, we have thus to consider aK-th category, called withdrawal, which contains (partially) missing data. We show how maximum likelihood estimation can be performed in this setup; whereas in discrete time our solution gives rigorous support to a solution often used in applications, in continuous time the maximum likelihood estimator of the transition matrix computed by means of the EM algorithm represents a significant improvement over existing methods.     

所有制结构调整与重庆产业结构调整

重庆产业结构调整不能只囿于产业结构本身进行 ,而应正视所有制结构调整在其中的重要性     

On Block Updating in Markov Random Field Models for Disease Mapping

Gaussian Markov random field (GMRF) models are commonly used to model spatial correlation in disease mapping applications. For Bayesian inference by MCMC, so far mainly single-site updating algorithms have been considered. However, convergence and mixing properties of such algorithms can be extremely poor due to strong dependencies of parameters in the posterior distribution. In this paper, we propose various block sampling algorithms in order to improve the MCMC performance. The methodology is rather general, allows for non-standard full conditionals, and can be applied in a modular fashion in a large number of different scenarios. For illustration we consider three different applications: two formulations for spatial modelling of a single disease (with and without additional unstructured parameters respectively), and one formulation for the joint analysis of two diseases. The results indicate that the largest benefits are obtained if parameters and the corresponding hyperparameter are updated jointly in one large block. Implementation of such block algorithms is relatively easy using methods for fast sampling of Gaussian Markov random fields ( Rue, 2001 ). By comparison, Monte Carlo estimates based on single-site updating can be rather misleading, even for very long runs. Our results may have wider relevance for efficient MCMC simulation in hierarchical models with Markov random field components.     

老工业基地技术创新与区域创新系统建设研究

分析了老工业基地技术创新不断重复着引进———落后———再引进———再落后的技术发展怪圈。指出在知识经济时代 ,技术发展的速度越来越快 ,单靠孤立的技术引进、技术改造、技术创新已经不能跟上科技创新的发展步伐。提出了加强区域创新系统建设 ,促进老工业基地技术创新的对策建议     

论中国实施战略性贸易政策的必要性及可能性

中国现行的“有管理的贸易自由化”阻碍了产业结构的优化,有必要实施战略性贸易政策。目前,中国实施战略性贸易政策的内部及外部约束条件已经可以得到满足,如中国可以充分利用WTO各项协议的例外条款和对发展中国家的特殊待遇,另外,中国也可以逐步满足不完全竞争市场结构与规模经济效应条件以及良好的市场经济运行体制条件。     

供应链企业间的合作轨道模型

文章主要介绍了轨道模型在供应链企业合作中的应用 ,根据合作程度的不同 ,伙伴企业处于以核心企业为中心的不同轨道。文章分别从静态和动态的角度运用轨道模型分析了企业间合作关系以及这种合作关系的变化。一方面使企业间的合作问题简单化 ;另一方面 ,轨道模型便于对合作问题进行深入的定量化研究。     

中小企业法的定位分析

中小企业法是政策法 ,政策目标是决定其定位的重要因素 ;根据我国中小企业目前发展中的突出问题 ,我国的中小企业法应定位于产业政策法     

美国跨国公司内部贸易问题研究

内部贸易已成为跨国公司实现其全球化战略的重要工具 ,并且跨国公司内部贸易在贸易方式、贸易规模上的实质性演变对整个国际贸易体系和世界经济发展方向的影响力度逐步加大 ,对我国整个国民经济的发展以及政策法规的制定都有重要的意义。因此 ,本文主要从美国跨国公司内部贸易的具体分析入手 ,对跨国公司内部贸易所独有特性和决定因素进行研究 ,以期望对我国跨国公司“走出去”的战略起到一定的指导作用。     

基于需求不确定性的供应链库存控制研究

通过建立需求不确定性环境下供应链成员的独立存货成本模型,运用模拟退火法对该模型进行52周的仿真,求解存货最佳订购数量与最佳再订购点,从而比较出不同存货控制策略的供应链存货总成本及订单满足率的差异。