Complement to a comparative analysis of heuristics for the <Emphasis Type="Italic">p</Emphasis>-median problem

A recent comparison of evolutionary, neural network, and scatter search heuristics for solving the p-median problem is completed by (i) gathering or obtaining exact optimal values in order to evaluate errors precisely, and (ii) including results obtained with several variants of a variable neighborhood search (VNS) heuristic. For a first, well-known, series of instances, the average errors of the evolutionary and neural network heuristics are over 10% and more than 1000 times larger than that of VNS. For a second series, this error is about 3% while the errors of the parallel VNS and of a hybrid heuristic are about 0.01% and that of parallel scatter search even smaller.     

A new family of lifetime models

We introduce a new family of distributions by adding a parameter to the Marshall–Olkin family of distributions. Some properties of the new family of distributions are derived. A particular case of the family, a three-parameter generalization of the exponential distribution, is given special attention. The shape properties, moments, distributions of the order statistics, entropies and estimation procedures are derived. An application to a real data set is discussed.     

On the convergence of two sequential Monte Carlo methods for maximum a posteriori sequence estimation and stochastic global optimization

This paper addresses the problem of maximum a posteriori (MAP) sequence estimation in general state-space models. We consider two algorithms based on the sequential Monte Carlo (SMC) methodology (also known as particle filtering). We prove that they produce approximations of the MAP estimator and that they converge almost surely. We also derive a lower bound for the number of particles that are needed to achieve a given approximation accuracy. In the last part of the paper, we investigate the application of particle filtering and MAP estimation to the global optimization of a class of (possibly non-convex and possibly non-differentiable) cost functions. In particular, we show how to convert the cost-minimization problem into one of MAP sequence estimation for a state-space model that is “matched” to the cost of interest. We provide examples that illustrate the application of the methodology as well as numerical results.     

Confidence intervals for the ratio of two variances

In this paper we consider confidence intervals for the ratio of two population variances. We propose a confidence interval for the ratio of two variances based on the t-statistic by deriving its Edgeworth expansion and considering Hall's and Johnson's transformations. Then, we consider the coverage accuracy of suggested intervals and intervals based on the F-statistic for some distributions.     

The Effect of Sensorimotor Training on the Postural Stability of Visually Impaired Women Over 50 Years of Age

Previous studies indicated that blind and visually impaired people are a group with greater risk of falls. Postmenopausal changes significantly decrease physical efficiency and impair the body’s mechanisms for maintaining postural stability. In addition, the frequency of falls among women is much higher than in men. The aim of this study was to analyze the effect of sensorimotor exercise on changes in postural stability of visually impaired women over 50 years of age. Visually impaired women from group E showed a lower level of postural stability measured with EO compared to the healthy women. After completing the exercise, a more pronounced improvement in the level of postural stability was observed in group E.     

An INAR(1) model based on a mixed dependent and independent counting series

A mixed integer-valued autoregressive model of order one, based on the binomial and the generalized binomial thinning operator is introduced. Geometric marginal distribution is considered. Properties of the model are analysed, unknown parameters are estimated and some numerical results of the estimates are obtained. Finally, model is applied on two real data sets and compared to some relevant models.     

Who are the Supporters of Croatian Membership in the European Union and NATO? Predictive Value of Personal and National Well-Being

Like many other Central and Eastern European countries Croatia has passed through substantial political changes and transition processes from state to liberal market economy in the last two decades. The next important step is accession to EU and NATO, and public opinion about joining these associations is divided. The aim of this study is to investigate the predictive value of subjective well-being measures in explaining attitudes of Croatian citizens toward accession to NATO and European Union. In particular, the prognostic utility of SWB is tested over and above usefulness of basic socio-demographic variables in explaining those political opinions. The research was conducted on a huge and representative sample (N = 4,000) of Croatian citizens in the spring of 2009. As a measure of subjective well-being, Croatian version of International Well-Being Index (IWI; Cummins in International Wellbeing Index, Version 2 [online]. Available from: , 2002) was used. IWI includes National and Personal Well-Being scales where each scale consists of several personal or national well-being domains. Socio-demographic variables used in this survey were gender, age, and level of education. Hierarchical logistic regression was applied to test the unique contribution of National and Personal well-being domains in predicting attitudes toward accession. The results show that National well-being index is useful in predicting attitudes toward accession of Croatia to EU and NATO, and has an even higher predictive value than basic socio-demographic variables. National well-being domains that significantly improve prediction were satisfaction with government and satisfaction with national economic situation. Higher satisfaction with national government is related to support of accession to both alliances, whereas higher satisfaction with national economy is associated solely with supporting the EU membership. The personal well-being index and belonging domains were not useful in this political attitude prediction. Possible theoretical explanation of observed relations between NWI and political opinion were further discussed.