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.     

Female board directors' resilience against gender discrimination

Despite regulatory efforts to promote gender diversity on boards, women are still severely underrepresented in board leadership in the UK, beyond FTSE 100 companies. Evidence suggests that women, when poorly represented in the workplace, are more likely to suffer discrimination. In this study, we report the first-hand experiences of gender discrimination suffered by female directors and present the process of how they build resilience through developing coping strategies. Such resilience-building processes seem to vary with the length of board experience of female directors. At the outset of their board journey, they adopt avoidant coping strategies of denial and disengagement. However, with experience in boards, they gain the confidence to pursue the active coping strategy of seeking and extending support. This qualitative study is based on 42 elite interviews of board directors and is guided by the resilience theory, in the context of top FTSE boards. The article also discusses the contribution of the study to theory, praxis, and policy.     

A simple integrated production policy of an imperfect item for vendor and buyer

This article develops a simple approach for determining an optimal integrated vendor–buyer inventory policy for an item with imperfect quality. The objective is to minimize the total joint annual costs incurred by the vendor and the buyer. This model is assumed to produce a certain number of defective items during the production process. Items of poor quality detected in the screening process of a lot are sold at a discounted price. The expected annual integrated total cost function is derived and a solution procedure is proposed to determine the optimal policy. Finally, a numerical example is also given to illustrate the solution procedure presented in this article.     

On a Multiple Three-Decision Problem for Comparing Several Treatments with the Best Control

In this article, a multiple three-decision procedure is proposed to classify p (≥2) treatments as better or worse than the best of q (≥2) control treatments in one way layout. Critical constants required for the implementation of the proposed procedure are tabulated for some pre-specified values of probability of no misclassification. Power function of the proposed procedure is defined and a common sample size necessary to guarantee various pre-specified power levels are tabulated under two optimal allocation schemes. Finally the implementation of the proposed methodology is demonstrated through numerical examples based on real life data.     

A Multiple Three-Decision Procedures for Comparing Several Treatments with a Control Under Heteroscedasticity

In this article, the design-oriented two-stage multiple three-decision procedure is proposed to classify a set of normal populations with respect to a control under heteroscedasticity. The statistical tables of percentage points and the power-related design constants, to implement our new two-stage procedure, are given. Sometimes when the sample for the second stage is not available, the one-stage data analysis procedure is proposed. Classifying a treatment better than control when it is actually worse (and vice versa) is known as type III error. Both the two-stage and one-stage procedures control the type III error rate at a specified level. The relationship between the two-stage and one-stage procedures is discussed. Finally, the application of the proposed procedures is illustrated with an example.     

Comparison of Operating Characteristics of Commonly Used Sample Size Re-Estimation Procedures in a Two-Stage Design

In group sequential clinical trials, there are several sample size re-estimation methods proposed in the literature that allow for change of sample size at the interim analysis. Most of these methods are based on either the conditional error function or the interim effect size. Our simulation studies compared the operating characteristics of three commonly used sample size re-estimation methods, Chen et al. (2004), Cui et al. (1999), and Muller and Schafer (2001). Gao et al. (2008) extended the CDL method and provided an analytical expression of lower and upper threshold of conditional power where the type I error is preserved. Recently, Mehta and Pocock (2010) extensively discussed that the real benefit of the adaptive approach is to invest the sample size resources in stages and increasing the sample size only if the interim results are in the so called “promising zone” which they define in their article. We incorporated this concept in our simulations while comparing the three methods. To test the robustness of these methods, we explored the impact of incorrect variance assumption on the operating characteristics. We found that the operating characteristics of the three methods are very comparable. In addition, the concept of promising zone, as suggested by MP, gives the desired power and smaller average sample size, and thus increases the efficiency of the trial design.     

The neurodevelopmental outcome in infants who have sustained a subdural haemorrhage from non‐accidental head injury

Subdural haemorrhage (SDH) in infants arises most commonly from non‐accidental head injury (NAHI) from shaking. Patients present with a varied severity of illness and a variety of symptoms and signs. Data on long‐term outcome of the survivors are not widely reported. The aim of this paper is to describe the physical and educational outcomes of children <2 years diagnosed with non‐accidental head injury and formulate guidelines on follow‐up. Data on 65 children <2 years with non‐accidental head injury and subdural haemorrhage diagnosed on CT/MRI/postmortem were extracted from the hospital and community notes and education reports. The Kings Outcome Scale for Childhood Head Injury (KOSCHI) was used. Sixteen children died (24.6%), 13 within 6 weeks and three 5 years after the injury. Of the 45 children followed up (follow‐up time 21.7–103 months), 25 had a good outcome, six were moderately disabled and 11 were severely disabled, while three were in persistent vegetative state. Problems identi?ed included cerebral palsy—16, ongoing seizures—5, visual problems—11, speech and language problems—17 and behavioural problems—13. Of the 29 children of school age on whom data were available, 12 children had a statement of educational needs. In conclusion, young children who survive non‐accidental head injury can have signi?cant physical, cognitive and behavioural problems. Regular follow‐up by a multidisciplinary team, which includes a community paediatrician, therapists, school health personnel and ophthalmologic services, until the child is established in school may facilitate early identi?cation of emerging problems and optimize management. Care must be taken not to discharge children with good outcomes, as behavioural and cognitive problems can emerge with time. Only a prospective study will help outline the subtle problems that can emerge with time in children with a so‐called good outcome. Copyright © 2004 John Wiley & Sons, Ltd.     

A comparative analysis of hijras and drag queens: the subversive possibilities and limits of parading effeminacy and negotiating masculinity

Gender studies in general and queer studies in particular have stressed the notion of imitation, play, and performance of gender. In this essay I undertake a comparative analysis of the hijra and the drag queen in terms of the shared and disparate subversive possibilities and limits of the gendered performances they undertake. Studying the hijra alongside the drag queen will in no way mean conflating the two categories. Rather, I explore the cultural nuances involved in the hijra performance, including its ritualistic and religious aspects. While my analysis relies heavily on previously written works about hijras and drag queens, I have also had the opportunity to meet and visit with hijras during several marriage ceremonies of cousins and other relatives from 1992 to 1998 in New Delhi.     

Some calibration estimators for finite population mean in two-stage stratified random sampling

Abstract

In the present article, an effort has been made to develop calibration estimators of the population mean under two-stage stratified random sampling design when auxiliary information is available at primary stage unit (psu) level. The properties of the developed estimators are derived in-terms of design based approximate variance and approximate consistent design based estimator of the variance. Some simulation studies have been conducted to investigate the relative performance of calibration estimator over the usual estimator of the population mean without using auxiliary information in two-stage stratified random sampling. Proposed calibration estimators have outperformed the usual estimator without using auxiliary information.     

Risk and protective factors in problem gambling: an examination of psychological resilience

Psychological resilience – successful adaptation when faced with adversity – is a product of the balance of risk and protective factors relevant to an outcome. This study examined if protective factors (perceived resilience; mindfulness; grit; self-efficacy) explained variance in problem gambling tendencies (assessed with the Problem Gambling Severity Index) beyond the HEXACO personality traits (honesty-humility, emotionality, extraversion, agreeableness, conscientiousness, openness to experience) and risk factors for problem gambling (gender; age; socio-economic status; high frequency gambling behaviour; harsh unpredictable childhood environments; sensation-seeking; impulsivity; self-control; stress). This study used a crowdsourced community sample (n = 469) recruited from Amazon Mechanical Turk. Bivariate analyses showed that risk factors and some HEXACO traits (especially honesty-humility) were associated with problem gambling issues. Among protective factors, only trait mindfulness showed a bivariate association with problem gambling issues. Somewhat surprisingly, regression analyses revealed that protective factors did not explain variance in problem gambling beyond HEXACO traits and risk factors. However, in exploratory analyses, mindfulness and self-efficacy – both modifiable protective factors – moderated the relationship between high-frequency gambling (a key proximate antecedent of problem gambling) and problem gambling tendencies. These results suggest mindfulness and self-efficacy may serve as ‘buffers’ against the development of problem gambling issues and may be promising targets for clinical interventions.