were published in the series as the contributed volume, Process Control
Performance Assessment: From Theory to Implementation with Andrzej
Ordys, Damian Uduehi, and Michael Johnson as Editors (ISBN
978-1-84628-623-0, 2007). Along with this good progress in process
controller assessment methods, researchers have also been investigating
techniques to diagnose what is causing the process or control loop
degradation. This requires the use of on-line data to identify faults
via new diagnostic indicators of typical process problems. A significant
focus of some of this research has been the issue of valve problems; a
research direction that has been motivated by some industrial statistics
that show up to 40% of control loops having performance degradation
attributable to valve problems. Shoukat Choudhury, Sirish Shah, and Nina
Thornhill have been very active in this research field for a number of
years and have written a coherent and consistent presentation of their
many research results as this monograph, Diagnosis of Process
Nonlinearities and Valve Stiction. The Advances in Industrial Control
series is pleased to welcome this new and substantial contribution to
the process diagnostic literature. The reader will find the exploitation
of the extensive process data archives created by today's process
computer systems one theme in the monograph. From another viewpoint, the
use of higher-order statistics could be considered to provide a
continuing link to the earlier methods of the statistical process
control paradigm.
