Evaluation of CUSUM and EWMA Control Charts to Detect Changes in Underlying Demand Trends of Naval Aviation Spares
Abstract
The Navy must keep aircraft in a high state of readiness around the globe requiring spare parts to be available when and where needed. Managers need to know when changes in demand patterns are occurring far enough in advance to ensure continued availability of needed spare parts. This thesis presents an evaluation of two techniques using widely available software operating in a Windows environment to determine if changes are occurring in underlying demand patterns. These techniques are Cumulative Sum Control Charting and Exponentially Weighted Moving Average Control Charting. The use of the techniques was validated using a computer generated data set with known variation characteristics, and related processes were developed. After validation, the techniques were applied to four actual data sets with demand information from Navy aircraft. Both techniques proved effective with Cumulative Sum Charting providing slightly earlier alarms, and Exponentially Weighted Moving Averages being easier to use. Use of these techniques could allow detection of changes in time to mitigate the negative effects of the change and could be applied to a very wide range of processes. For the Navy, the widespread use of these techniques could lead to more aircraft being available for combat missions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2010
- Accession Number
- ADA531664
Entities
People
- Les Wetherington
Organizations
- Naval Postgraduate School