A comparative study of FDI and BFTCS control performance is made for the following three subcases namely,
Nevertheless, the PI values indicate that the control performance of BFTCS and conventional control scheme are comparable despite the false alarms that are committed.
For sensor and parametric faults (as reported in Tables 5 and 6), the FDI and BFTCS control performance with the two different models for FDI and linear process simulation (FS-L and RO-L) are comparable in terms of number of successful detections, number of false alarms committed, cumulative bias estimated and the PI values.
In all the fault cases reported here (Tables 5-8), the non-linear process simulation deteriorates the FDI and BFTCS control performance when compared to the linear case because of the resulting process model mismatch.
Comparison of FDI and BFTCS control performance for the no fault case (PI)[X.sub.d] (PI)[X.sub.b] Model Successful No.
Histograms were charted to visually determine if normality existed for BFTC. Since this and other area sawmills use BFTC, a violation from normality and/or independence would mean that false decisions could be made via the use of traditional control charting.
The normal distribution was not appropriate to describe BFTC. As a result, traditional control charting (Shewhart control chart) would not adequately detect low outlying values.
Another concern is that the BFTC distributional properties will change from time to time, especially if a group of small- or large-diameter logs are run consecutively or nearly so.
Since mean log diameter can be dynamic, one could benefit by monitoring the diameter of every log coming in to account for the influence of log diameter on BFTC ratio.
However, after some investigation, this decreased variability was probably attributable to the fact that the mill consistently saw higher mean log diameters for oak than for poplar or pine, resulting in a decrease in BFTC error.
However, should a small sawmill be able to afford a weight scale, then a daily account of BFTC could be made.
BFTC ratio did not follow a normal distribution for any of the three major species processed at this sawmill.