Logistics support is a key element of aircraft transportation systems. This paper is concerned with the impact of aircraft spares provisioning decisions on the availability of aircraft. Spares provisioning in this context is complicated by the fact that spares may be shared across aircraft and that aircraft may have redundant systems. In addition, decisions concerning aircraft spares support re...

fault tolerance is one of the important issues in industries, such as transportation, military, chemical and nuclear sectors. reliability and safety are two vital attributes of fault tolerant systems, and redundancy is a common way to improve these parameters. this article studies the impact of including cold standby spares in system architecture. to do this, it uses the markov model of the sys...

In this paper, we treat the problem of stochastic comparison of standby [active] redundancy at component level versus system level. In the case of standby redundancy, we present some interesting comparison results of both series systems and parallel systems in the sense of various stochastic orderings for both the matching spares case and non-matching spares case, respectively. In the case of a...

A new parameter is introduced for modeling the reliability of systems with standby spares. Dependability, d, is defined as the conditional probability that the checker reports a module as good given that the module is good. The trade-off between the number of spares and dependability then is examined.

In a multi-location, exchangeable-item repair system with spares, the expected waiting time and the fill rate measures are oftentimes used as the optimization criteria for the spares allocation problem. These measures, however, do not take into account that customers will tolerate a reasonable delay and therefore, the firm does not incur reputation costs if customers wait less than their tolera...

The logistics resources (in the form of spare parts) for future exploration missions to the Moon and Mars can have significant mass and volume requirements. In this study it is shown that reconfigurable or common parts, that allow use of the same component in different mission elements, can be a means of reducing the required number of spares. A model for determining the system availability as ...

Models based on the crystal structure of interleukin-1 vary significantly. D eP ri st o/ El se vi er UK) warns that, for any given structure in the Protein Data Bank (PDB), there will be many other overlooked structures that are equally consistent with the data. Crystallized proteins retain the ability to move around, thus making interpretations of diffraction data an imprecise process. Crystal...