Bi-directional system analysis under copula-coverage approach

Reliability assessment is a major step, toward the development of fault-tolerant computing system. In different fields of engineering and physical/ailed sciences, researchers or engineers have several reliability approaches for the better performance of the system. By assuming different types of time trends, failure modes and repair effects, the legion stochastic model has been developed for repairable system. This study shows a novel concept for three state fault tolerant repairable systems with two types of repair. This research predicts the effect of the coverage factor using Gumbel-Hougaard family of copula approach on reliability characteristics of the designed system.     

A Bayesian approach to mixture cure models with spatial frailties for population‐based cancer relative survival data

As the treatments of cancer progress, a certain number of cancers are curable if diagnosed early. In population‐based cancer survival studies, cure is said to occur when mortality rate of the cancer patients returns to the same level as that expected for the general cancer‐free population. The estimates of cure fraction are of interest to both cancer patients and health policy makers. Mixture cure models have been widely used because the model is easy to interpret by separating the patients into two distinct groups. Usually parametric models are assumed for the latent distribution for the uncured patients. The estimation of cure fraction from the mixture cure model may be sensitive to misspecification of latent distribution. We propose a Bayesian approach to mixture cure model for population‐based cancer survival data, which can be extended to county‐level cancer survival data. Instead of modeling the latent distribution by a fixed parametric distribution, we use a finite mixture of the union of the lognormal, loglogistic, and Weibull distributions. The parameters are estimated using the Markov chain Monte Carlo method. Simulation study shows that the Bayesian method using a finite mixture latent distribution provides robust inference of parameter estimates. The proposed Bayesian method is applied to relative survival data for colon cancer patients from the Surveillance, Epidemiology, and End Results (SEER) Program to estimate the cure fractions. The Canadian Journal of Statistics 40: 40–54; 2012 © 2012 Statistical Society of Canada     

A resilience enhancing trauma-informed program for children and mothers in domestic violence shelters: A qualitative study

In domestic violence (DV) shelters, offering psychosocial support services to mothers and children is vital. The program ‘Time for Tony the Turtle’ has been developed for mothers and children residing in DV shelters in the Netherlands. It aims to foster attachment and regulation skills, which can also prepare for trauma treatment if sought after later on. This qualitative study explores the experiences of mothers, children and professionals with the program and its perceived impact and what components function as facilitators and barriers in the implementation of such a program in DV crisis shelters in the Netherlands. We conducted in-depth interviews with 15 mothers, 11 children and 18 professionals from three organizations offering DV shelters. We used thematic analysis to identify patterns of meaning in the interviews. Mothers, children and professionals valued that the program provided a calm moment for reflection in hectic times and that the playfulness in which the program addressed trauma-related topics. However, mothers find it difficult to attend the program in the beginning of their shelter stay, therefore hampering the applicability of the program. Our findings suggest that integrating the topic of discussing father in a program in crisis shelters is complex and deserves more attention.     

Reintegration upon return: insights from Ecuadorian returnees from Spain

Using the ECM2 survey data on Ecuadorian migrants returning from Spain, we investigate the determinants of reintegration upon return. We study how the migration experience, but also the before‐ and after‐migration characteristics, correlate with migrants’ outcomes upon return. We adopt a broad conception of reintegration, considering jointly labour market‐related outcomes that proxy for structural reintegration and subjective indicators that provide insights on sociocultural reintegration. The determinants of these two types of outcomes appear to be different: reintegration indeed encompasses multiple dimensions which cannot be captured by a single indicator. Our results suggest that return assistance programmes’ efficiency in helping reintegration could be improved by (I) targeting, ex‐ante, returnees who plan to launch their own business, and, ex‐post, the most vulnerable workers (women, older returnees, unemployed), and (ii) facilitating the labour market integration of foreign‐educated returnees. They also call for further research to better understand the consequences of these programmes.     

Genetic variants in ATP6 and ND3 mitochondrial genes are not associated with aggressive prostate cancer in Mexican–Mestizo men with overweight or obesity

Mitochondrial defects have been related to obesity and prostate cancer. We investigated if Mexican–Mestizo men presenting this type of cancer, exhibited somatic mutations of ATP6 and/or ND3.Body mass index (BMI) was determined; the degree of prostate cancer aggressiveness was demarcated by the Gleason score. DNA from tumor tissue and from blood leukocytes was amplified by the polymerase chain reaction and ATP6 and ND3 were sequenced. We included 77 men: 20 had normal BMI, 38 were overweight and 19 had obesity; ages ranged from 52 to 83. After sequencing ATP6 and ND3, from DNA obtained from leukocytes and tumor tissue, we did not find any somatic mutations. All changes observed, in both genes, were polymorphisms. In ATP6 we identified, in six patients, two non-synonymous nucleotide changes and in ND3 we observed that twelve patients presented non-synonymous polymorphisms. To our knowledge, this constitutes the first report where the complete sequences of the ATP6 and ND3 have been analyzed in Mexican–Mestizo men with prostate cancer and diverse BMI. Our results differ with those reported in Caucasian populations, possibly due to ethnic differences.     

ON FUZZY GOAL PROGRAMMING—SOME COMMENTS

This paper pertains to goal programming with fuzzy goals and fuzzy priorities. Hannan [1], in his paper on fuzzy goal programming, alludes to the difficulty of handling fuzzy priorities and further notes that a method that this author proposed [2] may lead to incorrect results. In this note, the general problem of goal programming with fuzzy priorities is reexamined, along with the solution to the specific example presented in my original paper [2]. It is shown that the method for handling fuzzy priorities originally proposed by this author does indeed capture the relative importance of goals.     

Different Factors for Different Causes: Analysis of the Spatial Aggregations of Fire Ignitions in Catalonia (Spain)

The present study analyzes the effects of different socioeconomic factors on the frequency of fire ignition occurrence, according to different original causes. The data include a set of documented ignition points in the region of Catalonia for the period 1995–2008. The analysis focused on the spatial aggregation patterns of the ignitions for each specific ignition cause. The point‐based data on ignitions were interpolated into municipality‐level information using kernel methods as the basis for defining five ignition density levels. Afterwards, the combination of socioeconomic factors influencing the ignition density levels of the municipalities was analyzed for each documented cause of ignition using a principal component analysis. The obtained results confirmed the idea that both the spatial aggregation patterns of fire ignitions and the factors defining their occurrence were specific for each of the causes of ignition. Intentional fires and those of unknown origin were found to have similar spatial aggregation patterns, and the presence of high ignition density areas was related to high population and high unemployment rates. Additionally, it was found that fires originated from forest work, agricultural activities, pasture burning, and lightning had a very specific behavior on their own, differing from the similarities found on the spatial aggregation of ignitions originated from smokers, electric lines, machinery, campfires, and those of intentional or unknown origin.     

Semiparametric Bayesian Techniques for Problems in Circular Data

In this paper, we consider the problems of prediction and tests of hypotheses for directional data in a semiparametric Bayesian set-up. Observations are assumed to be independently drawn from the von Mises distribution and uncertainty in the location parameter is modelled by a Dirichlet process. For the prediction problem, we present a method to obtain the predictive density of a future observation, and, for the testing problem, we present a method of computing the Bayes factor by obtaining the posterior probabilities of the hypotheses under consideration. The semiparametric model is seen to be flexible and robust against prior misspecifications. While analytical expressions are intractable, the methods are easily implemented using the Gibbs sampler. We illustrate the methods with data from two real-life examples.     

Avoiding the valley of death in educating strategists

Billions of dollars and hundreds of millions of hours are invested every year in executive education. However, much of this investment dies in a familiar “Valley of Death” (VoD) wherein what is learned in the classroom is not applied when the strategist returns back to work. Based on 30 in-depth interviews and live observation, we investigate the architecture of an executive education program designed to avoid the VoD. In the observed program, senior partners of a strategy consulting firm, and their key strategist clients, are brought together to co-learn strategy associated with scenario planning, and, at the same time, improve their ongoing business relations. We find that adopting a “paired learning structure” and utilizing “live case content” results in “group-level co-learning” (or the co-production of knowledge) that, participants report, avoids the VoD. This research contributes to the scholarship on learning architecture in executive education by establishing linkages to the literature on client-partner relationships, modelling the student, and service co-production in knowledge-intensive organizations, and, in the end, provides a blueprint that professional service firms and business schools, seeking to produce more value for their participants, can jointly emulate.