Date of Award


Degree Type


Degree Name

Master of Science (MS)


Mathematics and Statistics

Committee Chair(s)

Robert V. Canfield


Robert V. Canfield


It is often the case that equipment used by industry must be replaced with new equipment from time to time either because frequent malfunctions make it too costly to repair, or because the equipment has simply worn out. The new equipment often has the nature of either malfunctioning soon after installation due to manufacturing defects, or functioning for an extended period of time because it is free of these defects. For this reason, equipment is often given a preliminary running called the burn-in which gives no useful output but merely tests for manufacturing defects. Also, after a given amount of time, equipment is often replaced so as to avoid the added cost of a breakdown while under use. The term useful life is here used to denote the time period starting after burn-in time is reached and ending when replacement time is reached (Shooman, 1968).