Progressively censored variables sampling plans for two-parameter exponential distributions

Progressive censoring is quite useful in many practical situations where budget constraints are in place or there is a demand for rapid testing. Balasooriya & Saw (1998) present reliability sampling plans for the two-parameter exponential distribution, based on progressively censored samples. However, the operating characteristic (OC) curve derived in their paper does not depend on the sample size. This seems to be because, in their computations, they forget to consider the proportion of uncensored data, which also has an important influence on the subsequent developments. In consequence, their OC curve is only valid when there is no censoring. In this paper, some modifications are proposed. These are needed to obtain a proper design of the above sampling plan. Whenever at least two uncensored observations are available, the OC curve is derived in closed form and a procedure for determining progressively censored reliability sampling plans is also presented. Finally, the example considered by Balasooriya & Saw is used to illustrate the results developed in this paper for several censoring levels.     

A decision support system for modelling and implementing the supply network configuration and operations scheduling problem in the machine tool industry

This paper presents a decision support system to simultaneously solve the supply network configuration problem and the operations scheduling problem for the machine tool industry. A novel database structure, which is able to consider alternative operations and alternative bills of material, has been used. An algorithm for complete enumeration to determine all the feasible solutions using stroke graphs is introduced. A multiagent-based simulator evaluates the different key performance indicators that the supply network deals with for each alternative solution (e.g. workload, profits, delivery times, etc.) to determine that ‘satisficed’ by the collaborative decision-making among its members. A case study based on a Spanish company that assembles highly customised machines and tools in several European plants is considered. From the experiments results based on data linked to this industry, it will be demonstrated that the tool is potentially useful for stakeholders and for the central decision-maker to make decisions collaboratively in a multisite context case.     

The Joint Development of Traditional Bullying and Victimization With Cyber Bullying and Victimization in Adolescence

The present study investigated the stabilities of and interrelationships among traditional (i.e., face‐to‐face) bullying, traditional victimhood, cyber bullying, and cyber victimhood among adolescents over time. About 1,700 adolescents aged 11–16 years at Time 1 self‐reported levels of both bullying and victimization in four contexts (in school, outside of school, texting, and on‐line) annually for 2 years. Results indicated that all four dynamics were moderately stable over time. The following variables were found to bidirectionally reinforce and predict each other over time: traditional bullying and traditional victimization; traditional bullying and cyber bullying; and traditional victimization and cyber victimization. These results indicate that bullying and victimhood in both face‐to‐face and cyber‐based interactions are related but not identical interpersonal dynamics.     

Multidimensional Poverty in Paraguay: Trends from 2000 to 2015

The paper discusses Kenneth C. Land and Alex C. Michalos’ review and assessment of the evolution of research on social indicators, quality of life and well-being over the past fifty years. The contribution deals with the impacts of three major societal changes on the future research agenda of social indicators research: firstly, impacts of the changing class structure of post-industrial society, secondly, globalization impacts, including its economic, political, cultural and institutional dimensions, and thirdly, the impacts of an increasingly networked digitalization of production and consumption.     

Implementing Consumer Choice in Long‐term Care: The Impact of Individual Budgets on Social Care Providers in England

In common with many advanced welfare states, England has increasingly relied on consumerist principles to deliver both greater quality and improved efficiency in the long‐term care system. The Individual Budget (IB) pilots marked the next step in this process, through a new system of funding whereby greater control of resources is given to service users, in lieu of direct in‐kind care provision. IBs have the potential to transform the market for care services as well as the relationships between key stakeholders within it. Purchasing will increasingly be shaped by the demands of IB holders, with providers expected to deliver a wider range of personalized services. What will this mean for providers, and what can they do to prepare for these changes? These questions are relevant not just in England but in many other countries adopting similar mechanisms for devolving control over the design, delivery and funding of care to the end‐user. The article explores the early impact of IBs on providers' services, on their workforces, and on the administrative implications for providers of managing IBs. The study finds that providers were positive about the opportunities for better‐quality services that IBs can bring about. However, participants highlighted a number of obstacles to their effectiveness, and reported a range of potentially adverse administrative and workforce consequences which have the potential to jeopardize the consumerist policy objectives of increased choice and efficiency.     

A nonparametric symmetry test for absolutely continuous bivariate copulas

Based on the works by Klement and Mesiar (Comment Math Univ Carolinae 47:141–148, 2006) and Nelsen (Stat Pap 48:329–336, 2007) on maximal asymmetry of copulas, we define and study the concept of tri-symmetry and we propose a simple statistic to test symmetry of a bivariate copula, given a random sample of an absolutely continuous bivariate random vector. We also make a power comparison against some other well known nonparametric symmetry tests.     

Some Relationships Between Skew-Normal Distributions and Order Statistics from Exchangeable Normal Random Vectors

The article explores the relationship between distributions of order statistics from random vectors with exchangeable normal distributions and several skewed generalizations of the normal distribution. In particular, we show that the order statistics of exchangeable normal observations have closed skew-normal distributions, and that the corresponding density function is log-concave when the order statistic is extreme. Special attention is given to the bivariate case, which is related to the univariate skew-normal distribution. The applications discussed focus on the lifetimes of coherent systems.     

Some characterizations of multivariate distributions using products of the hazard gradient and mean residual life components

We give a general procedure to characterize multivariate distributions by using products of the hazard gradient and mean residual life components. This procedure is applied to characterize multivariate distributions as Gumbel exponential, Lomax, Burr, Pareto and generalized Pareto multivariate distributions. Our results extend the results of several authors and can be used to study how to extend univariate models to the multivariate set-up.     

A New Measure of Fit for Equations With Dichotomous Dependent Variables

The econometrics literature contains many alternative measures of goodness of fit, roughly analogous to R ², for use with equations with dichotomous dependent variables. There is, however, no consensus as to the measures' relative merits or about which ones should be reported in empirical work. This article proposes a new measure that possesses several useful properties that the other measures lack. The new measure may be interpreted intuitively in a similar way to R ² in the linear regression context.     

The past,present and future of policy modeling

We evaluate the past, present, and future of policy modeling from both qualitative and quantitative perspectives. We do this through an extensive review and analysis of papers published in the Journal of Policy Modeling between 1978 and 2018. Over the years the focus of the policy modeling literature (and the Journal) changed. The changes were in research topics, approaches, techniques, theories, methods, and analytical tools as required for the rigorous analysis of complex and dynamic economic phenomena in policy modeling.