Advances in capital replacement modelling with applications

Bouamra, O

Abstract

This thesis addresses the capital replacement modelling problems associated with a
mixed, or inhomogeneous, fleet and also takes account of the fleet size problem.
Applications considered relate to a fleet of buses and a fleet of medical equipment. The
initial chapters introduce the notion of capital replacement modelling and review
previous work in the field, as well as reviewing the fleet size problem. Replacement
policies are also put in the context of the fleet rather than the context of a 'typical plant'.
In the third chapter, we present our first attempt to model capital replacement with
variable fleet size over a finite planning horizon. A two cycle model is developed in
which the notion of penalty cost for breakdown is introduced. This cost is incurred when
demand is not met. To take account of the cost of unmet demand, a simple failure model
for plant is proposed. The replacement model is applied to a fleet of ventilators in an
intensive care unit of a hospital. In the fourth chapter we develop various models for the
case of replacement of a sub-fleet within a mixed fleet. These models themselves have
variable finite planning horizon of variable length and build on developments described
earlier in the thesis. Other aspects such as the increased cost of sub-optimal policy due
to delayed replacement, smaller replacement sub-fleet etc. are also considered. The
models developed in chapter 4 are applied, in the following chapter, to a fleet of buses
operated by a Malaysian inter-city bus company. Sensitivity analysis on different factors
is also carried out. Finally the sensitivity of optimal decision policy to the choice of the
replacement model is described in the context of the bus application.

Citation

Bouamra, O. Advances in capital replacement modelling with applications. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Sep 16, 2011
• Publicly Available Date: Sep 16, 2011
• Award Date: Jan 1, 1996