Joint Ordering and Pricing Strategies for Managing Substitutable Products

Starr and Rubinson (1978) develop a model to establish the relationship between product demand and relative prices. The notion of relative prices motivates us to consider a situation in which a retailer would either charge the same retail price for all products if he adopts a ‘fixed’ pricing strategy or charge different prices for different products if he adopts a ‘variable’ pricing strategy. In this paper, we develop a base model with deterministic demand that is intended to examine how a retailer should jointly determine the order quantity and the retail price of two substitutable products under the fixed and variable pricing strategies. Our analysis indicates that the optimal retail price under the variable pricing strategy is equal to the optimal retail price under the fixed pricing strategy plus or minus an adjustment term. This adjustment term depends on product substitutability and price sensitivity. We also present two different extensions of our base model. In the first extension, our analysis indicates that the underlying structure of the optimal retail price and order quantity is preserved when there is a limit on the total order quantity. The second extension deals with the issue of retail competition. Relative to the base case, we show that the underlying structure of the optimal retail price and order quantity is preserved in a duopolistic environment. Moreover, our analysis suggests that both retailers would adopt the variable pricing strategy at the equilibrium.     

Multistage sampling for latent variable models

I consider the design of multistage sampling schemes for epidemiologic studies involving latent variable models, with surrogate measurements of the latent variables on a subset of subjects. Such models arise in various situations: when detailed exposure measurements are combined with variables that can be used to assign exposures to unmeasured subjects; when biomarkers are obtained to assess an unobserved pathophysiologic process; or when additional information is to be obtained on confounding or modifying variables. In such situations, it may be possible to stratify the subsample on data available for all subjects in the main study, such as outcomes, exposure predictors, or geographic locations. Three circumstances where analytic calculations of the optimal design are possible are considered: (i) when all variables are binary; (ii) when all are normally distributed; and (iii) when the latent variable and its measurement are normally distributed, but the outcome is binary. In each of these cases, it is often possible to considerably improve the cost efficiency of the design by appropriate selection of the sampling fractions. More complex situations arise when the data are spatially distributed: the spatial correlation can be exploited to improve exposure assignment for unmeasured locations using available measurements on neighboring locations; some approaches for informative selection of the measurement sample using location and/or exposure predictor data are considered.     

Profile information matrix for nonlinear transformation models

For semiparametric models, interval estimation and hypothesis testing based on the information matrix for the full model is a challenge because of potentially unlimited dimension. Use of the profile information matrix for a small set of parameters of interest is an appealing alternative. Existing approaches for the estimation of the profile information matrix are either subject to the curse of dimensionality, or are ad-hoc and approximate and can be unstable and numerically inefficient. We propose a numerically stable and efficient algorithm that delivers an exact observed profile information matrix for regression coefficients for the class of Nonlinear Transformation Models [A. Tsodikov (2003) J R Statist Soc Ser B 65:759-774]. The algorithm deals with the curse of dimensionality and requires neither large matrix inverses nor explicit expressions for the profile surface.     

培养复合型外语人才的教学模式探析

能力型外语人才培养模式要求建立并充分利用 CAI系统进行基础知识的教学 ,采用主题教学的课堂教学模式 ,把课上学习与课下学习结合起来 ,加强课外实践活动 ,并采用新的评估方法对学生成绩进行综合评估。     

Recurrence in Workers' Compensation Claims: Estimates from a Multiple Spell Hazard Model

This paper estimates both single and multiple spell hazard models using a sample of workers' compensation claims (with soft tissue musculoskeletal injuries) from Ontario, Canada. Most of the results in this paper are consistent with the estimates in the existing literature. However, the duration elasticities for workers' compensation benefits and pre-injury earnings from the multiple spell hazard models are much larger than the estimates from the single spell models. This suggests that the estimates in existing literature that use single spell hazard models may underestimate the effect of benefits and pre-injury earnings on the duration of soft tissue musculoskeletal claims.     

Parameterization and inference for nonparametric regression problems

We consider local likelihood or local estimating equations, in which a multivariate function () is estimated but a derived function () of () is of interest. In many applications, when most naturally formulated the derived function is a non-linear function of (). In trying to understand whether the derived non-linear function is constant or linear, a problem arises with this approach: when the function is actually constant or linear, the expectation of the function estimate need not be constant or linear, at least to second order. In such circumstances, the simplest standard methods in nonparametric regression for testing whether a function is constant or linear cannot be applied. We develop a simple general solution which is applicable to nonparametric regression, varying-coefficient models, nonparametric generalized linear models, etc. We show that, in local linear kernel regression, inference about the derived function () is facilitated without a loss of power by reparameterization so that () is itself a component of (). Our approach is in contrast with the standard practice of choosing () for convenience and allowing ()> to be a non-linear function of (). The methods are applied to an important data set in nutritional epidemiology.     

Recovering Information from Incremental Responses

Some yields analysed and reported in the literature have been adjusted by subtracting a control. It is found that full information can be recovered for estimable parameters and the error variance using these incremental responses, in comparison with unadjusted data. These findings are of practical importance, and they supplement materials usually found in a graduate course in linear inference. The issues are illustrated using a case study from the literature.     

《设备故障诊断与维修》课程的改革构思与初步实践

本文介绍了《设备故障诊断与维修》课程在教学内容、教学模式、教学方法及手段等方面的改革构思与实践。以加强综合、强化实践 ,突出创新为突破口 ,进行教学改革 ,能有效地提高教学质量。     

浅析完全学分制下的学生管理模式

随着高等教育事业的发展和招生规模的扩大 ,高校学生工作正面临着机遇和挑战。本文立足于本校的实际情况 ,对在完全学分制下建立三种新的学生管理模式 ,进行了有益的探索。     

网络文学的兴起与文学创作模式的嬗变

随着互联网的蓬勃发展 ,文学网站、网络文学频道及个人文学主页应运而生。它为网络写手、网民中的文学读者、网络文学评论家提供了与传统文学迥异的在线写作、在线阅读、在线评论这种新的文学活动方式和文学活动空间。网络文学蔚然兴起。它具有的革命性意义是突破了传统的文学创作模式 ,实现了从口头文学创作到书面文学创作再到网络文学创作的质的变化