Efficient arrangements of two-level orthogonal arrays in two and four blocks

When orthogonal arrays are used in practical applications, it is often difficult to perform all the designed runs of the experiment under homogeneous conditions. The arrangement of factorial runs into blocks is usually an action taken to overcome such obstacles. However, an arbitrary configuration might lead to spurious analysis results. In this work, the nice properties of two-level orthogonal arrays are taken into consideration and an effective method for arranging experimental runs into two and four blocks of the same size is proposed. This method is based on the so-called J-characteristics of the corresponding array. General theoretical results are given for studying up to four experimental factors in two blocks, as well as for studying up to three experimental factors in four blocks. Finally, we provide best blocking arrangements when the number of the factors of interest is larger, by exploiting the known lists of non-isomorphic orthogonal arrays with two levels and various run sizes.     

Statistical inference for the Gompertz distribution based on Type-II progressively hybrid censored data

In this article, the statistical inference for the Gompertz distribution based on Type-II progressively hybrid censored data is discussed. The estimation of the parameters for Gompertz distribution is obtained using maximum likelihood method (MLE) and Bayesian method under three different loss functions. We also proved the existence and uniqueness of the MLE. The one-sample Bayesian prediction intervals are obtained. The work is done for different values of the parameters. We apply the Monto Carlo simulation to compare the proposed methods, also an example is discussed to construct the Prediction intervals.     

Slashed generalized exponential distribution

In this paper, we introduce an extension of the generalized exponential (GE) distribution, making it more robust against possible influential observations. The new model is defined as the quotient between a GE random variable and a beta-distributed random variable with one unknown parameter. The resulting distribution is a distribution with greater kurtosis than the GE distribution. Probability properties of the distribution such as moments and asymmetry and kurtosis are studied. Likewise, statistical properties are investigated using the method of moments and the maximum likelihood approach. Two real data analyses are reported illustrating better performance of the new model over the GE model.     

Slashed generalized Rayleigh distribution

We introduce a new family of distributions suitable for fitting positive data sets with high kurtosis which is called the Slashed Generalized Rayleigh Distribution. This distribution arises as the quotient of two independent random variables, one being a generalized Rayleigh distribution in the numerator and the other a power of the uniform distribution in the denominator. We present properties and carry out estimation of the model parameters by moment and maximum likelihood (ML) methods. Finally, we conduct a small simulation study to evaluate the performance of ML estimators and analyze real data sets to illustrate the usefulness of the new model.     

Theory and methods for partitioned Gini coefficients computed on post-stratified data

The Gini coefficient is used to measure inequality in populations. However, shifts in the population distribution may affect subgroups differently. Consequently, it can be informative to examine inequality separately for these segments. Consider an independently and identically distributed sample split based on ranking and compute the Gini coefficient for each partition. These coefficients, calculated from post-stratified data, are not functions of U-statistics. Therefore, previous theoretical and methodological results cannot be applied. In this article, the asymptotic joint distribution is derived for the partitioned coefficients and bootstrap methods for inference are developed. Finally, an application to per capita income across census tracts is examined.     

The effects of under‐skilling on need for recovery,losing employment and retirement intentions among older office workers: A prospective cohort study

Based on a sample of older workers from the Maastricht Cohort Study, the authors investigate the prevalence and dynamics of self‐reported under‐skilling and its effects on workers' need for recovery, their risk of losing employment and their retirement intentions over a two‐year period. They find that being under‐skilled is associated both with higher levels of need for recovery over time and with the risk of losing employment, but not with early retirement intentions. To achieve sustainable employment, they argue, the course of under‐skilling should be monitored throughout workers' careers, enabling timely interventions to avoid its negative consequences.     

Creativity in social work education and practice: reflections on a Survivor Arts Project

This article, written by survivor artists, practitioners and academics (each moving between these different identities and associated voices), will explore a creative arts approach to social work (SW) education within the context of service user and carer involvement. In addition to building upon a developing literature base, the writers will draw upon their own experience and the experience of other service user and carer contributors as well as student and practitioner feedback. In doing so, this article will seek to analyse some of the ways the creative arts can be harnessed as a tool for a more radical, creative and critical approach to professional education and how this in turn can help develop more empathic, critically self-reflective and creative (in the broadest sense of the word) practitioners. In critiquing the more traditional service user and carer involvement approach, this article will attempt to show how the more innovative approach of the Survivor Arts Project can move us beyond an arguably more limiting ‘expertise through experience’ model. In outlining an emancipatory model which recognises the relevance of lived experience and places this within the context of survivor movements, focusing also on the skills and insights survivors bring to SW education, this article will detail the ways we can work towards developing a more vibrant and dynamic learning environment which values our life stories and recognises our strengths as well as the many different and overlapping identities which place us along a continuum that connects our lives and informs our practice.     

Managing dependency in China outsourcing relationships

Abstract

This paper examines manufacturing firms’ use of guanxi and formal control to address dependence on suppliers and achieve desired outsourcing performance in China. Using survey data collected from manufacturing firms operating in China, a structural equation model is used to test the research model. The results suggest that manufacturing firms with high dependence on suppliers build Chinese guanxi with those suppliers to overcome the dependence and enhance outsourcing performance. In addition, Chinese guanxi also appears to facilitate the use of formal control, which was also found to have a positive relationship with outsourcing performance. This paper contributes to the literature by illustrating the importance of guanxi in achieving desired outsourcing performance in the China context, particularly in the case where a manufacturer perceives high dependency on its major supplier.