Backorder Estimation under Multiple Failures of Lower Indenture Items: A Technical Note
Abstract
Most multiechelon, multiindenture stockage models used by the Military Services and industry are extensions of the basic Multi-Echelon Technique for Recoverable Item Control (METRIC) model. Those models assume that the failure of an item is due to the failure of one and only one next lower indenture item, although more than one lower indenture item failure is observed in many real-world situations. Under such assumptions, the METRIC theory overstates backorders, often dramatically, and that overstatement results in a misallocation of spares budgets. This document considers two types of failure detection mode for lower indenture items: simultaneous and sequential. For both problems, the author developed mathematical models that produce good lower and upper bonds on the true solutions. Interpolation formulas based on univariate regression provide an estimate of the true solution. In the simultaneous detection problem, METRIC's more than 300 percent average absolute error has been reduced to less than 4 percent on a sample of 120 simulation cases; in the sequential problem, the error is reduced from 9 percent to 6 percent. The maximum errors are reduced more dramatically. The new analytic procedures are easy to calculate, and they should be relatively easy to incorporate into computer programs for spares optimization.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1988
- Accession Number
- ADA201140
Entities
People
- Craig C. Sherbrooke
Organizations
- LMI