Three Bartlett-type corrections for score statistics in symmetric nonlinear regression models

We present simple matrix formulae for corrected score statistics in symmetric nonlinear regression models. The corrected score statistics follow more closely a χ ² distribution than the classical score statistic. Our simulation results indicate that the corrected score tests display smaller size distortions than the original score test. We also compare the sizes and the powers of the corrected score tests with bootstrap-based score tests.     

A clustering method for global optimization based on thekth nearest neighbour

In this paper we describe a stochastic method for global optimization based on a uniform sampling in the search domain. After a reduction of the sample, computing the distance between the remaining points and using the distribution of the kth nearest neighbour enables clusters of points to be built up, hopefully fitting the regions of attraction of significant local optima; from each of these a local search is started. The properties of the method are analysed, and detailed computational results on standard test functions are provided.     

Forthcoming in Sociological Forum

Forthcoming in Sociological Forum     

A comment on “A theoretical basis for perturbation methods” by Krishnamurty Muralidhar and Rathindra Sarathy

Statistics and Computing -     

Optimal sequential Bayesian analysis for degradation tests

Degradation tests are especially difficult to conduct for items with high reliability. Test costs, caused mainly by prolonged item duration and item destruction costs, establish the necessity of sequential degradation test designs. We propose a methodology that sequentially selects the optimal observation times to measure the degradation, using a convenient rule that maximizes the inference precision and minimizes test costs. In particular our objective is to estimate a quantile of the time to failure distribution, where the degradation process is modelled as a linear model using Bayesian inference. The proposed sequential analysis is based on an index that measures the expected discrepancy between the estimated quantile and its corresponding prediction, using Monte Carlo methods. The procedure was successfully implemented for simulated and real data.     

Outlines of a Critical Sociology of Consumption: Beyond Moralism and Celebration

The 'new' sociology of consumption that emerged in the 1980s acknowledged that consumption is a significant cultural and social practice and not just a mere signifier of the pathological elements of contemporary societies. Arguably, this rehabilitation of consumption has overshot its mark and has led to an overly positive, complacent and celebratory rendering of consumption and to an overriding concern with the symbolic and communicative dimension of goods. Driven by the debates on globalization, political consumerism and the relation between consumption and citizenship, current work shows increased interest in the politics of consumption. The article explores in what directions the classic concern with the symbolic and communicative dimension of goods might be taken if it is more thoroughly grounded in an analysis of the politics of consumption and of the current reconfigurations of consumers and citizens. The overall aim is to outline a basis for a critical sociology of consumption.     

China Brotsky,Sarah M. Eisinger,and Diane Vinokur-Kaplan: Shared Space and the New Nonprofit Workplace

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations -