In this paper we consider three topics in reliability and maintenance. Their
common feature is the explicit consideration of interdependence, either amongst
components within a machine, amongst stages in a logistics chain, or amongst machines
sharing maintenance facilities.
Chapter 1 examines measures of the contribution of a component towards a
system's reliability; these measures include structural importance, marginal reliability
importance, joint reliability importance, and link importance. We review these different
measures and examine how they relate to each other. We show that some structural
results previously derived for independent components continue to hold for associated
components. We then propose extensions to each importance measure to cover
components which have two failure modes rather than the conventional one, and show
that these extensions largely retain the properties of the original definitions.
Chapter 2 examines a system containing one machine subject to random failure, for
which we wish to determine a maintenance policy and a spare ordering policy. We
consider the solvability and desirability of jointly optimizing these two traditionally
separate policies. We discuss why the general form of the problem is intractable and show
how it might be approached using bounds and heuristic policies; more importantly, we
examine several special cases which are more tractable. Particular attention is paid to
systems which contain only one spare at a time; we show that these systems have some
convexity properties which facilitate cost minimization. We subsequently consider
systems which allow more than one spare, but make use of other restrictions or
assumptions to simplify analysis.
Chapter 3 examines how to coordinate maintenance for machines sharing repair
facilities, a task which is commonly called the machine repairman problem. Existing
studies of this problem make the restrictive assumption that repairs are performed only
after machine failure; our work extends the machine repairman model by allowing
preventive repair. We derive analytical results for a single critical age repair policy, and
then use numerical studies to investigate other heuristic policies which can improve the
system's cost effectiveness.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/6241 |
| Date | 11 1900 |
| Creators | Armstrong, Michael John |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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