Offering warranty for a second-hand item stimulates the sales of the item, but at the same time, it accumulates additional warranty servicing cost. This additional cost can be reduced through actions that improve the reliability of the item, such as overhaul and upgrade. An upgrade action brings...

Burn-in is a widely used engineering method of elimination of defective items before they are shipped to customers or put into field operation. Under the assumption that a population is described by the decreasing or bathtub-shaped failure rate functions, various optimal burn-in problems have...

Half a century ago Strehler and Mildvan (1960) have published the seminal paper that, based on some assumptions (postulates), theoretically ‘justified’ the Gompertz law of mortality. It also defined the, so called, Srehler-Mildvan correlation between the parameters of the Gompertz...

It is well known that life expectancy can be expressed as an integral of the survival curve. The reverse - that the survival function can be expressed as an integral of life expectancy - is also true.

Burn-in is a widely used engineering method of elimination of defective items before they are shipped to customers or put into field operation. In conventional burn-in procedures, components or systems are subject to a period of simulated operation prior to actual usage. Then those which failed...

Some properties of the mean residual lifetime (MRL) functions are studied. The main focus is on relative characteristics. It is proved that under certain assumptions the relative hazard rate ordering leads to the corresponding ultimate MRL ordering. This result is applied to stochastic...

Vaupel (1998) posed the provocative question, “When it comes to death, how do people and flies differ from Toyotas?†He suggested that as the force of natural selection diminishes with age, structural reliability concepts can be profitably used in mortality analysis. Vaupel (2003) went...

A bivariate competing risks problem is considered for a rather general class of survival models. The lifetime distribution of each component is indexed by a frailty parameter. Under the assumption of conditional independence of components the correlated frailty model is considered. The explicit...

Cohort measures, describing a lifetime random variable are easily and unambiguously obtained using standard tools. On the contrary, the lifetime random variable, and therefore life expectancy, for the period setting cannot be unambiguously defined without additional simplifying assumptions. For...

The article analyzes how a defender determines a balance between protecting an object (passive defense) and striking preventively against an attacker seeking to destroy the object (active defense). The attacker analogously determines a balance between attacking and protecting against the...