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...

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...