This article discusses the variability ordering of lifetimes of parallel systems with two independent heterogeneous exponential components in terms of the right spread order. It is proved, among others, that the reciprocal majorization order between the two hazard rate vectors implies the right spread order between the lifetimes of two parallel systems. The result is then extended to the proportional hazard rate model as well. The results established here extend and enrich those known in the literature. 相似文献
The presence of strategic attackers has become an important factor in the security and protection of systems, especially since the 9/11/2001 attacks, and considerable efforts have been dedicated to its study. When defending against the strategic attacker, many existing studies assume that the attacker would seek to minimize the defender's utility, which implies that the defender and attacker have symmetric utilities. However, the attacker's objective is determined by its own valuation of the system and target of the attack, which is not necessarily consistent with the defender's utility. If the attacker unexpectedly targets a different utility, then the defense strategy might no longer be optimal. In particular, the defense strategy could be inferior if the attacker's utility is not known to the defender. This study considers a situation where the defender's utility is the system survivability and the attacker's utility is the expected number of destroyed elements in the system. We investigate possible attack strategies under these two different utilities and compare (a) the conservative defense strategy when the attack utility is unknown to the defender with (b) the optimal defense strategy when the attack utility is known to the defender. We show that the conservative protection strategy is still optimal under asymmetric utilities when the contest intensity is smaller than one. 相似文献
A nonprofit’s reputation is a crucial intangible asset that can bring significant benefits to the organization. Using a multidimensional framework, this study tested the effects of three dimensions of nonprofit reputation—financial efficiency, media visibility, accreditation status—on charitable giving behavior. The findings of this 2 × 2 × 2 full-factorial survey experiment show that each of the reputation dimensions has a significant individual effect on giving behavior. Furthermore, financial efficiency and accreditation status have an interaction effect on giving behavior. The findings also demonstrate the cross-level interaction between financial efficiency and the real-life giving behavior of individuals and between accreditation and the real-life volunteering behavior. This study provides implications for our understanding of the components of nonprofit reputation and their impact on charitable giving.