Some problems in reliability of systems composed of unreliable components
The thesis considers several connected problems in the study of
reliability of systems with unreliable components. Initially it
reviews the dichotomic case introducing a new characterization which
clarifies the importance of the k-out-of-n structures. This
characterization is applied to two problems, failure to operate and to
idle and stress-strength modelling. Whilst most previous work has
concerned itself with coherent structures, being thought of as
reasonable systems, the latter section of the chapter considers the
case of non-coherent structures. The following chapter moves from the
dichotomic models to multilevel models, considering possible .
extensions and producing a hierarchy within the possible definitions.
Chapter 3 considers the stochastic properties of such systems, again
attension is paid to the k-out-of-n structures and non-coherent
models. The final two chapters consider component performance. In
chapter 4 the system is assumed to be hierarchical,, so that a
component is part of a subsystem, and it is assumed the whole
subsystem may be replaced. The effect on the component is examined.
The final chapter considers optimal age replacement of a component
considering 3 possible alternative criteria.