Small Parts Aspiration, Ingestion, and Choking in Small Children: Findings of the Small Parts Research Project

Obtaining information on current child injury trends and their associated issues is an important factor in developing products that meet or surpass acceptable toy safety boundaries. Understanding these boundaries helps determine safe product design characteristics that reduce the risk of product-related injury. Inchcape Testing Services developed a Small Parts Aspiration, Ingestion, and Choking Hazards Research Project, independent of an ongoing consumer Product Safety Commission (CPSC) project. The project's purpose was to determine, independent of CPSC, whether a more stringent small parts regulatory standard was necessary and, if so, to ensure that the standard was determined objectively. This article reports on the project's findings relating to critical characteristics (size, shape, and consistency) relative to the victim's age, of objects responsible for child choking injuries and fatalities.     

Managing Multiple Facets of Risk in New Product Alliances*

The trend of forming alliances to develop new products continues; however, many of these new product alliances fail. As such we explore how key risk types intrinsic in new product alliances, performance, relational, and knowledge appropriation risks, influence alliance success. Further, we theorize that different alliance governance mechanisms can reduce the negative impact of risks on alliance success. To disentangle possible heterogeneous factors across firms that may affect the interplay of risk assessments and the use of governance mechanisms, we employ latent class regression analysis on survey data collected from 128 new product alliance firms and find support for a two‐regime solution. Longer alliance relationships and lower technological turbulence are factors for some firms (regime one), while the opposite are factors for other firms (regime two). These two regimes show different patterns in the interplay of risk assessments and governance for alliance success. Our theory and results support viewing risk as a multiple‐factor concept and by understanding the different impacts of the risk types in new product alliances and how governance mechanisms mitigate such effects, we aid managers' decision making regarding the balance of contractual versus normative governance in new product alliances. Understanding the heterogeneous factors inherent in these complex relationships enables managers to understand the conditions in which various governance mechanisms promote new product alliance success.     

Supply Chain Conflict Due to Store Brands: The Value of Wholesale Price Commitment in a Retail Supply Chain*

Store brands are of increasing importance in retail supply chains, often causing channel conflict, as the retailer's product directly competes with the manufacturer's national brand. Extant research on the resulting channel interactions either assumes the national brand manufacturer can credibly commit to maintaining a wholesale price or that he lacks such ability. However, these two scenarios imply very different supply chain interactions, as only a national brand manufacturer with commitment ability can strategically adjust a national brand wholesale price to prevent a store brand introduction by the retailer. We specifically analyze the impact of this assumption on the manufacturer, the retailer, and the customers. We determine when long‐term contracts that provide the manufacturer with such commitment ability can improve supply chain profitability.     

战略导向、组织学习对产品创新的影响研究

本文对战略导向影响产品创新的路径进行了研究,发现不同战略导向对学习活动有不同的选择倾向,而不同类型的学习活动也会对产品创新产生不同的影响。本研究不仅弥补了应用性学习与探索性学习研究的不足,也有助于企业引导和利用组织学习来提高产品创新水平,为管理实践提供理论参考。     

Simple Formulae for Evaluating the Potential Impact of Confounding Bias

Unmeasured confounding is a common problem in observational studies. This article presents simple formulae that can set the bounds of the confounding risk ratio under three standard populations of the exposed, unexposed, and total groups. The bounds are derived by considering the confounding risk ratio as a function of the prevalence of a covariate, and can be constructed using only information about either the exposure–confounder or the disease–confounder relationship. The formulae can be extended to the confounding odds ratio in case–control studies, and the confounding risk difference is discussed. The application of these formulae is demonstrated using an example in which estimation may suffer from bias due to population stratification. The formulae can help to provide a realistic picture of the potential impact of bias due to confounding.     

Relations for Moments of Progressively Type-II Censored Order Statistics from Log-Logistic Distribution with Applications to Inference

In this article, we establish several recurrence relations for the single and product moments of progressively Type-II right censored order statistics from a log-logistic distribution. The use of these relations in a systematic recursive manner would enable the computation of all the means, variances and covariances of progressively Type-II right censored order statistics from the log-logistic distribution for all sample sizes n, effective sample sizes m, and all progressive censoring schemes (R ₁,…, R _m ). The results established here generalize the corresponding results for the usual order statistics due to Balakrishnan and Malik (1987 Balakrishnan , N. , Malik , H. J. ( 1987 ). Moments of order statistics from truncated log-logistic distribution . J. Statist. Plann. Infer. 17 : 251 – 267 .[Crossref], [Web of Science ®] , [Google Scholar]) and Balakrishnan et al. (1987 Balakrishnan , N. , Malik , H. J. , Puthenpura , S. ( 1987 ). Best linear unbiased estimation of location and scale parameters of the log-logistic distribution . Commun. Statist. Theor. Meth. 16 : 3477 – 3495 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). The moments so determined are then utilized to derive best linear unbiased estimators for the scale- and location-scale log-logistic distributions. A comparison of these estimates with the maximum likelihood estimates is made through Monte Carlo simulation. The best linear unbiased predictors of progressively censored failure times is then discussed briefly. Finally, a numerical example is presented to illustrate all the methods of inference developed here.     

A-optimal designs for heteroscedastic multifactor regression models

Abstract

This paper searches for A-optimal designs for Kronecker product and additive regression models when the errors are heteroscedastic. Sufficient conditions are given so that A-optimal designs for the multifactor models can be built from A-optimal designs for their sub-models with a single factor. The results of an efficiency study carried out to check the adequacy of the products of optimal designs for uni-factor marginal models when these are used to estimate different multi-factor models are also reported.     

Recurrence formula on the joint distribution of sample skewness and kurtosis under normality

Abstract

Two recurrence relations with respect to sample size are given concerning the joint distribution of skewness and kurtosis of random observations from a normal population: one between the probability density functions and the other between the product moments. As a consequence, the latter yields a recurrence formula for the moments of sample kurtosis. The exact moments of Jarque-Bera statistic is also given.     

VARIATION REDUCTION AND ROBUST DESIGNS

In this paper we consider two strategies for variation reduction. One of them is the exploitation of interactions. We also discuss the role of experiments in discovering interactions and in particular the use of robust designs to obtain the interaction between control and noise factors. Then we attempt to reduce the variation in a measurement system using a robust design.     

Progressive type II censored order statistics from exponential distributions

In the model of progressive type II censoring, point and interval estimation as well as relations for single and product moments are considered. Based on two-parameter exponential distributions, maximum likelihood estimators (MLEs), uniformly minimum variance unbiased estimators (UMVUEs) and best linear unbiased estimators (BLUEs) are derived for both location and scale parameters. Some properties of these estimators are shown. Moreover, results for single and product moments of progressive type II censored order statistics are presented to obtain recurrence relations from exponential and truncated exponential distributions. These relations may then be used to compute all the means, variances and covariances of progressive type II censored order statistics based on exponential distributions for arbitrary censoring schemes. The presented recurrence relations simplify those given by Aggarwala and Balakrishnan (1996)