Modeling Disinterest and Dislike: A Bounded Bayesian Mixed Logit Model of the UK Market for GM Food

Mixed logit models represent a powerful discrete choice analytical model but require assumptions about the functional form of the parameter distributions. The use of unbounded distributions, such as the normal distribution, may be regarded as unsuitable where theory indicates that all are negatively affected by increases in an attribute, such as price. Bounded distributions such as the triangular and log-normal are unable to model the case where a section of the population is indifferent towards an attribute, while the remainder are negatively disposed toward it. Train and Sonnier’s bounded mixed logit model accommodates these features and is employed in this paper. A censored normal and Johnson’s S_b distribution are used to model preferences in the UK for food attributes, including price and GM technology. Bi-modal distributions are identified regarding GM food: some are unlikely to ever consume it, some are close to indifference and willing to consume at relatively small discounts while the remainder are fairly unresponsive to further price reductions.     

数据拟合回归方法的探讨

建立回归方程进行分析预测,大多采用人们熟知的"最小二乘法"。但是"最小二乘法"有本质上的一个弱点,由于系数矩阵的病态性质:系数矩阵中的最大值相对很大,系数矩阵的行列式值相对较小,在求解方程时,系数中的微小变化可能导致结果不稳定,预测效果不佳甚至失真。本文另辟蹊径,与"最小二乘法"的拟合原则不同,我们是最小化误差绝对值中的最大值。该法克服了"最小二乘法"有时不稳定的缺陷,继而提高拟合精度,使预测效果更精确。     

我国制造业环境管制的实证研究

从制造业的角度出发,分析了政府对环境管制(ER)的两种形式:正式管制(FER)和非正式管制(I-ER),建立了环境管制均衡方程,并且采用面板数据的分析方法对理论假设进行了验证。研究表明,假设的影响制造业环境管制的主要因素:政府保护意愿、劳动密集程度、产业规模、经济外向度、产业国有化程度、科技吸收转化支出和劳动力素质的高低均产生了显著的影响。     

Endogenous structural change and crisis in a multiple time-scales growth model

The slow and endogenous twist of economic macro-structure makes up an important evolutionary feature of capitalist economies, and may be at the root of structural crisis. In this line, a Goodwinian growth model with increasing returns and profit-sharing that tries to picture a simple scenario of the seventies crisis is considered. It is shown that the exhaustion of the Kaldor-Verdoorn “productivity law” can entail, in a nonlinear framework, a “catastrophic” bifurcation from a “high” to a “low” growth path. Slow/fast dynamical systems then allow one to formalize a multiple time-scales dynamics where the growth path is shaped by the structural framework in which it takes place, but has also a long -un feedback. Structural change and crisis appear as long term and endogenous outcomes.     

基于投入产出与解释结构建模法相结合的产业关联及层次识别建模

将投入产出方法与解释结构建模相结合,取长补短,提出了基于这两种方法相结合的产业关联层次识别的分析方法,并呈现了该方法的算法步骤、识别层次结果的基本特性以及其与以往产业关联分析方法的比较优势.最后以经统一调整的1997及2002年投入产出表为基础,对我国国民经济产业关联的层次识别进行实证分析,经对识别结果的跨期对比分析,证明该识别方法的解释效果良好.     

物流系统建模方法的研究

通过对现有系统建模分析方法的比较和分析,针对物流系统提出了一种集成建模分析GI-SIM法。该方法以概念、功能和动态建模思想为基础,以GRAI格、IDEFO和仿真技术为建模工具,满足了复杂物流系统的建模要求。最后,给出了GI-SIM法的建模步骤,并对其进行了总结和评价。     

物流系统规划-仿真集成化技术研究

通过对物流系统规划与仿真模型的分析，归纳出系统规划模型与系统仿真模型的共有属性和关系，采用集成化的技术，建立集成化规划一仿真系统模型，并通过Solidworks和Flexsim研究实现其集成化，并在相关课题中获得成功应用，突破了现有软件在规划与仿真之间数据共享的壁垒。     

军用车辆器材调拨业务流程重组模型研究

基于信息流分析,论述了军用车辆器材调拨系统中信息流程和业务流程的重组和优化应用,采用对象、岗位、任务三维视图的建模方法描述核心业务流程,提高了系统的可读性和可推广性。     

中国航空货运顾客价值动因的实证研究

通过考察中国航空货运,建立航空顾客价值的决定因素与动态性理论模型,运用结构方程方法对其检验,结果表明:时间因素和便捷性因素是影响货运顾客价值的核心要素,价格因素已退之其次,而且来自竞争者、服务商、顾客、宏观环境的变化都对顾客价值动态性有显著影响。     

Using replication research for just-in-time purchasing construct development

Using replication research, the validity of the just-in-time purchasing (JITP) construct is established. Although empirical researchers have examined JITP over the last two decades, a consistent set of valid, reliable factors has not been used. The lack of valid construct is a barrier to hypotheses testing and meta-analyses on JITP. This study confirmed the validity of six JITP factors: top management commitment, employee relations, training, supplier quality management, transportation, and quantities delivered using two different data sets and testing the first- and second-order structure of the JITP construct. Content validity, reliability, unidimensionality, convergent validity, discriminant validity, criterion-related validity, and an invariant factorial structure of the JITP construct were empirically established.