Demand and Production Management with Uniform Guaranteed Lead Time

Recently, innovation‐oriented firms have been competing along dimensions other than price, lead time being one such dimension. Increasingly, customers are favoring lead time guarantees as a means to hedge supply chain risks. For a make‐to‐order environment, we explicitly model the impact of a lead time guarantee on customer demands and production planning. We study how a firm can integrate demand and production decisions to optimize expected profits by quoting a uniform guaranteed maximum lead time to all customers. Our analysis highlights the increasing importance of lead time for customers, as well as the tradeoffs in achieving a proper balance between revenue and cost drivers associated with lead‐time guarantees. We show that the optimal lead time has a closed‐form solution with a newsvendor‐like structure. We prove comparative statics results for the change in optimal lead time with changes in capacity and cost parameters and illustrate the insights using numerical experimentation.     

国外农户经济理论研究述评

农户经济理论是农村研究的重要分支领域.国外农户经济理论研究历史悠久、学派众多并互有采借.在我国"工业反哺农业"、大力缩小城乡差距的今天,对国外农户经济理论进行建设性反思批判仍然具有非常重要的意义.本文在国内已有研究文献的基础上,从历史发展的角度,兼顾各理论流派的理论争论与交锋,结合中国当前"城乡二元社会结构"的特殊国情,对国外农户经济理论进行了系统梳理,并指出其对中国研究的意义与局限,以期为农户经济研究提供借鉴和参考.     

英语网络交互教学研究的现状与发展趋势

大量研究证实,交互性是语言教学的灵魂,而“交互活动”的质量与外语教学与学习的成效正相关。从“交互性”视角出发．综述分析国内外外语网络教学研究现状可国内英语网络交互教学研究的发展趋势如下：1）关于英语网络教学“交互性”和“交互活动”的研究,2）关于英语网络交互教学体系的设计、构建与完善,3）对英语网络交互教学的成效与影响因素的科学分析。     

推动地方服务业大发展的十项举措

"十二五"期间,我国大多数地区将迎来服务业大发展的难得机遇.政府与市场是促进地方服务业大发展的两大力量.从政府的角度,应从转变观念、因地制宜、产业政策、财税政策、金融政策、制度环境、载体建设、工作机制、项目带动及育才引才等十个方面着手,充分发挥政府的引领作用和调控作用,推进地方服务业的跨越式发展.     

国外农户经济研究理论述评

从五个方面评述了国外农户经济理论:农户经济理论的经典研究;道义小农与理性小农的争论及其综合;把风险和家庭时间纳入分析框架的风险规避理论和农场户理论;海外中国研究中的农户经济理论和工农业关系中的农户经济理论。不同理论流派都有其视野局限,在运用国外农户经济理论分析中国农户经济问题时必须坚持建设性反思批判精神。     

中国金融机构的系统重要性及系统性风险传染机制分析——基于复杂网络的视角

采用最小生成树(MST)和平面极大过滤图(PMFG)方法构建和分析金融市场网络可以动态识别金融网络中节点的系统重要性,而利用最小生成树的唯一性可以全面而直观地显示系统性风险的传导机制。我们通过对银行间同业拆借市场进行的实证分析证明了该方法的有效性和稳健性,特别是最小生成树方法对系统性风险传导潜在路径的识别以及系统性风险的宏观审慎监管提供了直观而有效的手段。     

Linear regression model with new symmetric distributed errors

Regression models play a dominant role in analyzing several data sets arising from areas like agricultural experiment, space experiment, biological experiment, financial modeling, etc. One of the major strings in developing the regression models is the assumption of the distribution of the error terms. It is customary to consider that the error terms follow the Gaussian distribution. However, there are some drawbacks of Gaussian errors such as the distribution being mesokurtic having kurtosis three. In many practical situations the variables under study may not be having mesokurtic but they are platykurtic. Hence, to analyze these sorts of platykurtic variables, a two-variable regression model with new symmetric distributed errors is developed and analyzed. The maximum likelihood (ML) estimators of the model parameters are derived. The properties of the ML estimators with respect to the new symmetrically distributed errors are also discussed. A simulation study is carried out to compare the proposed model with that of Gaussian errors and found that the proposed model performs better when the variables are platykurtic. Some applications of the developed model are also pointed out.     

作业成本动因选择、合并与评价的系统方法构建

目前学术界关于作业成本动因选择与合并的研究,缺乏对动因留选与留选个数的探讨,而关于对成本动因选择合并的评价的研究未见。可以通过聚类分析建立模型,得到成本动因的相关类,再结合主成分分析指导留选动因的个数,最终确定留选动因,并首次建立评价动因选择与合并优劣性的主成分分析模型。实证分析表明,此系统方法更好地解决了成本动因选择与合并的问题,相同数据下该方法比矩阵理论与距离聚类分析结果更优,作业成本管理系统的复杂性与信息成本显著降低。本文为作业成本动因的选择与合并以及评价提供了一套系统方法。     

生物药品制造行业竞争战略影响企业绩效的时滞效应研究——基于VAR模型的脉冲响应分析

本文利用中国医药生物制品上市公司2003年1季度-2012年1季度的季度财务数据进行了验证性因子分析,构建了差异化和低成本两个因子以反映公司的竞争战略。在此基础上,利用向量自回归(VAR)和脉冲响应的思路考察了战略制定及实施后企业的绩效表现,确定了战略绩效的滞后程度。研究发现:竞争战略影响企业绩效表现出一定的时滞效应;且差异化战略影响企业绩效的滞后期长于低成本战略;同时竞争战略影响企业绩效具有持续性,即竞争战略能够给企业带来持续的竞争优势,且差异化战略影响企业绩效的持续时间相比低成本战略也更长。最后,实证结果还发现,在医药生物制品行业,差异化战略相比低成本战略实施难度更大,风险更高,实施成功的可能性越小。     

Uncertainty Analysis Based on Probability Bounds (P-Box) Approach in Probabilistic Safety Assessment

A wide range of uncertainties will be introduced inevitably during the process of performing a safety assessment of engineering systems. The impact of all these uncertainties must be addressed if the analysis is to serve as a tool in the decision-making process. Uncertainties present in the components (input parameters of model or basic events) of model output are propagated to quantify its impact in the final results. There are several methods available in the literature, namely, method of moments, discrete probability analysis, Monte Carlo simulation, fuzzy arithmetic, and Dempster-Shafer theory. All the methods are different in terms of characterizing at the component level and also in propagating to the system level. All these methods have different desirable and undesirable features, making them more or less useful in different situations. In the probabilistic framework, which is most widely used, probability distribution is used to characterize uncertainty. However, in situations in which one cannot specify (1) parameter values for input distributions, (2) precise probability distributions (shape), and (3) dependencies between input parameters, these methods have limitations and are found to be not effective. In order to address some of these limitations, the article presents uncertainty analysis in the context of level-1 probabilistic safety assessment (PSA) based on a probability bounds (PB) approach. PB analysis combines probability theory and interval arithmetic to produce probability boxes (p-boxes), structures that allow the comprehensive propagation through calculation in a rigorous way. A practical case study is also carried out with the developed code based on the PB approach and compared with the two-phase Monte Carlo simulation results.