Application of Markov chain Monte Carlo methods to modelling birth prevalence of Down syndrome

Data collected before the routine application of prenatal screening are of unique value in estimating the natural live-birth prevalence of Down syndrome. However, much of these data are from births from over 20 years ago and they are of uncertain quality. In particular, they are subject to varying degrees of underascertainment. Published approaches have used ad hoc corrections to deal with this problem or have been restricted to data sets in which ascertainment is assumed to be complete. In this paper we adopt a Bayesian approach to modelling ascertainment and live-birth prevalence. We consider three prior specifications concerning ascertainment and compare predicted maternal-age-specific prevalence under these three different prior specifications. The computations are carried out by using Markov chain Monte Carlo methods in which model parameters and missing data are sampled.     

一类供应链的线性转移支付激励机制研究

针对不同的供应链设计不同的契约是供应链协作的一个重要手段。在由一个零售商和一个供应商组成的供应链中,零售商的促销努力水平对供应链的效率有重大的影响,本文提出了一种线性转移支付激励机制,且证明了在该机制的作用下,零售商将付出对整个供应链最优的促销努力水平,这时供应链的总收益将得到提高,而对新增收益的划分则取决于供应商和零售商之间的讨价还价能力。     

The impact of supply chain management practices on competitive advantage and organizational performance

Effective supply chain management (SCM) has become a potentially valuable way of securing competitive advantage and improving organizational performance since competition is no longer between organizations, but among supply chains. This research conceptualizes and develops five dimensions of SCM practice (strategic supplier partnership, customer relationship, level of information sharing, quality of information sharing, and postponement) and tests the relationships between SCM practices, competitive advantage, and organizational performance. Data for the study were collected from 196 organizations and the relationships proposed in the framework were tested using structural equation modeling. The results indicate that higher levels of SCM practice can lead to enhanced competitive advantage and improved organizational performance. Also, competitive advantage can have a direct, positive impact on organizational performance.     

考虑质量失误的供应链博弈模型研究

在理性的制造商和供应商组成的二级供应链中,考虑存在产品质量失误的情况下,通过最优化方法选择中间品的质量水平和制造商的检测水平,以实现供应链的利润最大化.并结合实际情况,根据质量内部、外部失误的不同承担方式,讨论了三种质量损失承担方式,得到在整体损失由两者共同承担的情况下,通过制定合理的内、外部损失分配系数,可以使两者选择水平的纳什均衡解与供应链的全局最优解相符,从而实现供应链全局最优和局部最优的一致.所得结论对指导供应链的有效运作有着较好的实际意义和参考价值.     

信息共享程度对物流外包激励契约的影响

本文分析了由供应商、制造商和第三方物流企业(3PLs)组成的物流外包系统,考虑了供应商和制造商信息共享程度的影响,建立了协同工作环境下的激励契约模型.结果表明,委托人偏好低努力水平时,信息共享对激励契约没有影响;委托人偏好高努力水平时,信息共享能更好的激励代理人选择委托人希望的行动.信息不共享时,3PLs只有提高对供应商努力水平的积极性;信息共享时,3PLs收入波动性增大,提高对供应商和对制造商的努力水平都能使其获得帕累托改进.本研究为物流成本在供应链成员中的分摊提供了理论依据,并提出了模型改进和研究建议.     

金融工程中资产收益的连续时间模型评述

总结了在过去30年中金融资产收益连续时间模型的发展及主要成果,讨论了迄今连续时间模型参数估计的主要方法,其中特别讨论了MCMC方法;最后指出了现在和未来该领域研究所面临的主要课题。     

基于MCMC稳态模拟的贝叶斯经验费率厘定信用模型

B黨lmann-Straub model is one of the most famous applications of the Bayesian method for the experience rate making.However,by the traditional B黨lmann-Straub model one cannot get the unbiased posterior estimation of the parameters when there is not sufficient prior information for the structural parameters;What's more,the difficult of computing high dimension numeration limits the application of Bayesian method.This paper introduces the Markov chain Monte Carlo simulaton method based on the Gibbs sampling after analyzing the structure of the B黨lmann-Straub model and sets up the Bayesian credibility model for estimating the predictive risk premium.Also by using the results of the numeration analysis,this paper proves that from this model one can get the posterior distributions of the parameters dynamically and the posterior estimation of the censoring parameters in the situation that exists unknown parameters,as well as improve the precision of the numeration,which can be helpful to find the heterogeneity of the premium.     

基于反向物流的商品定价和退货政策研究

综述了基于反向物流的商品定价和退货政策的最新研究成果。在此基础上,通过建立模型,对基于反向物流的商品定价策略和退货政策进行了进一步的研究,并求出了商品的最优价格和最优退货价格。基于模型,对管理提出了一些建议。最后指出了将来可能的研究方向。     

基于提前期的多阶通用件库存模型

针对单个企业内部应用通用件的环境,在假定一个多阶生产系统的基础上,对应用通用件的库存量水平及其成本进行了分析,建立了多阶通用件库存模型,提出通过对采用通用件和不采用通用件的成本差异的比较,来决策多阶生产系统中在哪一阶工序采用通用件,并求解出每一阶工序优化的基本库存水平。     

带有快速反应策略供应链系统的补偿策略研究

过长的订购提前期往往使得零售商订货决策感到困难. 快速反应策略能使零售商在获 得更多更准确的市场需求信息后,调整订购量而提高收益. 但是快速反应策略并不一定使供应 商的利润也提高. 有文章指出只有低的服务水平才能使两者利润同时提高,因而这种方法在工 业应用中是不一定可行的. 补偿策略是一种广泛应用的方法,能够提高产品的客户服务水平, 因而研究了补偿策略在快速反应供应链系统中的作用. 在某些条件下,在快速反应供应链系统 中,补偿策略能使零售商与供应商一方的收益不变或者提高,另一方的收益有所提高,即Pare2 to 提高. 还研究了引进补偿策略后,供应链系统的最优解及期望卖出量、期望缺货量和期望残 余量的变化情况.