Nonparametric confidence intervals for Tmax in sequence-stratified crossover studies

Tmax is the time associated with the maximum serum or plasma drug concentration achieved following a dose. While Tmax is continuous in theory, it is usually discrete in practice because it is equated to a nominal sampling time in the noncompartmental pharmacokinetics approach. For a 2-treatment crossover design, a Hodges-Lehmann method exists for a confidence interval on treatment differences. For appropriately designed crossover studies with more than two treatments, a new median-scaling method is proposed to obtain estimates and confidence intervals for treatment effects. A simulation study was done comparing this new method with two previously described rank-based nonparametric methods, a stratified ranks method and a signed ranks method due to Ohrvik. The Normal theory, a nonparametric confidence interval approach without adjustment for periods, and a nonparametric bootstrap method were also compared. Results show that less dense sampling and period effects cause increases in confidence interval length. The Normal theory method can be liberal (i.e. less than nominal coverage) if there is a true treatment effect. The nonparametric methods tend to be conservative with regard to coverage probability and among them the median-scaling method is least conservative and has shortest confidence intervals. The stratified ranks method was the most conservative and had very long confidence intervals. The bootstrap method was generally less conservative than the median-scaling method, but it tended to have longer confidence intervals. Overall, the median-scaling method had the best combination of coverage and confidence interval length. All methods performed adequately with respect to bias.     

Estimation and Confidence Regions for Parameter Sets in Econometric Models1

This paper develops a framework for performing estimation and inference in econometric models with partial identification, focusing particularly on models characterized by moment inequalities and equalities. Applications of this framework include the analysis of game‐theoretic models, revealed preference restrictions, regressions with missing and corrupted data, auction models, structural quantile regressions, and asset pricing models. Specifically, we provide estimators and confidence regions for the set of minimizers Θ_I of an econometric criterion function Q(θ). In applications, the criterion function embodies testable restrictions on economic models. A parameter value θthat describes an economic model satisfies these restrictions if Q(θ) attains its minimum at this value. Interest therefore focuses on the set of minimizers, called the identified set. We use the inversion of the sample analog, Q_n(θ), of the population criterion, Q(θ), to construct estimators and confidence regions for the identified set, and develop consistency, rates of convergence, and inference results for these estimators and regions. To derive these results, we develop methods for analyzing the asymptotic properties of sample criterion functions under set identification.     

Multiproduct,Multicriteria Model for Supplier Selection with Product Life‐Cycle Considerations

In industrial purchasing contexts firms often procure a set of products from the same suppliers to benefit from economies of scale and scope. These products are often at different stages of their respective product life cycles (PLCs). Firms consider multiple criteria in purchasing such products, and the relative importance of these criteria varies depending on the PLC stage of a given product. Therefore, a firm should select suppliers and choose sourcing arrangements such that product requirements across multiple criteria are satisfied over time. The extant models in sourcing literature for evaluating and selecting suppliers for a portfolio of products have not considered this important and practical issue faced by firms. This article proposes a mathematical model that effectively addresses this issue and contributes to the sourcing literature by demonstrating an approach for optimally selecting suppliers and supplier bids given the relative importance of multiple criteria across multiple products over their PLC. The application of the model on a hypothetical data set illustrates the strategic and tactical significance of such considerations.     

Generalized inferences on the common mean vector of several multivariate normal populations

The hypothesis testing and confidence region are considered for the common mean vector of several multivariate normal populations when the covariance matrices are unknown and possibly unequal. A generalized confidence region is derived using the concepts of generalized method based on the generalized p$p$-value. The generalized confidence region is illustrated with two numerical examples. The merits of the proposed method are numerically compared with those of existing methods with respect to their expected area or expected d-dimensional volumes and coverage probabilities under different scenarios.     

法学难点案例研究与教学：合格产品的产品责任

利用案例研究进行法学难点问题的教学是法学教育的重要形式.本文试图通过对王英诉白酒标识应加警示标志案的个案分析,阐明我国产品责任法理论研究和课堂教学中的难点问题——合格产品的产品责任,即合格产品也可能存在产品缺陷,对造成他人人身财产损害的,也应承担相应的赔偿责任.     

等价无穷小在求复合函数极限中的应用

在求复合函数极限过程中,对其内函数进行等价无穷小代换,给出若干有用结果。     

大型重载轴承CAD系统的研究与开发

介绍了一种基于轴承“极限负荷设计法”的智能化、专业化CAD系统 ,改变了传统轴承设计的设计周期长、分析计算繁杂且计算结果不准确、不易实现最优化参数设计的缺陷。该系统已经在成都科华重型轴承有限公司推广使用     

数列极限比较理论

给出数列极限比较式定义 ,由此简明地导出极限理论 .证明了该定义等价于原定义(ε-N) ,以及单调子列定理、单调归结原则等 .该理论不仅便于教学 ,而且揭示了数列极限可归结到单调数列 ,最终归结到自然数列     

Bipolar value-driven joint product costing

There exists a joint-cost allocation problem in the public sector, particularly highlighted by the cost-based national pricing of blood products in England, supposedly derived using volume-driven activity-based costing (ABC): an approach criticised by the implementation criteria propounded for ABC within the academic literature. In contrast, we believe that the contributions of quality-associated operations-based drivers, described within ABC, together with the net realisable value method, usually recommended as the optimal joint-cost allocation method, provide the beginnings of a solution. This paper sets out a methodological development from this platform that links allocation decisions with the issue of value. The bipolar nature of the model is based upon the combination of two types of allocation. One allocates joint costs according to the altered value of source material when competing non-joint alternative products exist. The other allocates joint costs according to product outcome values ascertained separately for the physical specification elements that comprise each of the range of joint products. The overall emphases are on academic context, model generalisation, the facilitation of cost-effective choices between joint products and non-joint alternatives, and possible future trends in the application of the method.     

The product cycle model of foreign direct investment and developing country welfare

Raymond Vernon's product-cycle model predicts two distinctive kinds of foreign direct investment in developing countries: fist, subsidiaries whose operations are tightly integrated into the parent's strategy to advance its competitive position in international markets; second, subsidiaries toward the host market whose profits help fund the needs of the parent but whose output is not an integral part of the parent's global sourcing network. In practice, the latter are frequently subject to domestic content, joint venture, and technology-sharing requirements; the former almost never are. How do the two kinds of foreign direct investment differ in their impact on host country development? Somewhat surprisingly, to those who may be wary of what Vernon himself reffered to as “captive” plants, foreign investor operations intimately linked into the parent's global sourcing network make a systematically larger and more dynamic contribution to the host economy via the activities of the affiliates themselves, via backward linkages to local suppliers, and via spillovers and externalities. Foreign investor operations impeded from close integration via domestic content, joint venture, and technology-sharing requirement provide a much less positive and sometimes genuinely negative impact, especially if they are protected by trade barriers or other forms of market exclusivity.