Detecting changes of steady states using the mathematical theory of evidence

✍ Scribed by S. Narasimhan; Chen Shan Kao; R. S. H. Mah

• Publisher: American Institute of Chemical Engineers
• Year: 1987
• Tongue: English
• Weight: 290 KB
• Volume: 33
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690331125

✦ Synopsis

The detection of changes in steady states is important in quality control, data reconciliation, and process monitoring applications. In a previous paper (Narasimhan et al., 1986) a composite statistical test was developed and evaluated for this purpose. In this note we present and evaluate an alternative method based on the mathematical theory of evidence developed by Shafer (1976). A key element of this approach is the assignment of beliefs to the different propositions of interest. This step usually involves subjective judgment. In this note we propose to make it less subjective by using the probability distribution of the measurements and certain limiting conditions. Simulation studies were carried out to compare the performance of this method with the multivariate statistical test developed by Narasimhan et al. (1986). The results show that both methods give the same performance. Thus this approach is an attractive alternative for detecting changes of steady states when the variables are independent. The belief function proposed here may also be used in other applications such as fault diagnosis (Kramer, 1987).