In this paper, we introduce a new shared frailty model called the compound negative binomial shared frailty model with three different baseline distributions namely, Weibull, generalized exponential and exponential power distribution. To estimate the parameters involved in these models we adopt...

An original dataset referring to a medium-sized Italian university is implemented for analyzing the determinants of scientific research production at individual level. Three different indicators, based on the number of publications and/or citations, are considered. Their distributions are highly...

Purpose – This paper aims to propose a new approach to setting the control limits to promote the control performance of the cumulative count of conforming chart ( CCC - r chart), in terms of the average number of items inspected (ANI). Design/methodology/approach – In contemporary high-yield...

Purpose – The purpose of this paper is to introduce the zero‐modified distributions in the calculation of operational value‐at‐risk. Design/methodology/approach – This kind of distributions is preferred when excess of zeroes is observed. In operational risk, this phenomenon may be due...

In this paper, we propose a random intercept Poisson model in which the random effect is assumed to follow a generalized log-gamma (GLG) distribution. This random effect accommodates (or captures) the overdispersion in the counts and induces within-cluster correlation. We derive the first two...

We consider a renewal risk model with phase-type claims, and obtain an explicit expression for the joint transform of the time to ruin and the number of claims until ruin, with a penalty function applied to the deficit at ruin. The approach is via the duality between a risk model with phase-type...

Purpose – The purpose of this paper is to introduce the zero-modified distributions in the calculation of operational value-at-risk. Design/methodology/approach – This kind of distributions is preferred when excess of zeroes is observed. In operational risk, this phenomenon may be due to the...