The diagnosability of discrete event systems has been a topic of interest to many researchers. The diagnosability conditions for various systems have evolved based on a regularity condition that is imposed on faulty traces with respect to their observable continuations. Improving upon this weak but necessary condition, a new model of diagnosability that is based on sensor outputs, which are called observatio ns, upon a command in put is proposed in this paper. Necessary and sufficient con ditions are derived for the proposed diagnosability model. The search performance of the proposed diagnosability condition is of linear complexity in terms of the power set of the system events and observations, compared to the exponential complexity of the search with the existing diag nosability regularity condition. Moreover, a system that is not diag no sable according to the existi ng diag nosability condition may be diagnosable in the proposed diagnosability model, which includes observations.
Control Theory and Technology
Corresponding author:S.RESHMILA,E-mail: email@example.com. Tel.:+91 9447231897;fax:+0484 2762541.S. RESHMILA received the B.Tech degree in Electrical and Electronics Engineering from the Mahatma Gandhi University in 1998 and the M.Tech degree in Embedded Systems from the Calicut University in 2007. She is currently a Ph.D. can didate in Electrical Engineering at Hindustan Institute of Technology and Science, Chennai. Her research interests are in model-based fault diagnosis and discrete event system;Devanathan RAJAGOPALAN received his Ph.D. and M.Sc.(Eng.) from Queen's University, Kingston, Ontario, Canada and his B.E. and M.E. degrees from Indian Institute of Science, Bangalore, India. Dr. Devanathan has taught at Nanyang Technological University (NTU), Singapore for over two decades. He has published over 160 papers in in ternational and national conference proceedings and journals, and has received awards from IEEE Education Society and NTU. He has chaired and co-chaired international conferences organized by IEEE as well as NTU. Currently he is Professor Emeritus in Electrical & Electronic Engineering in Hindustan Institute of Technology and Science, Chennaiz India. His interests include control systems, nonlinear systems, robotics, image processing, discrete event systems and quantitative linguistics. He is a life senior member of IEEE. E-mail: firstname.lastname@example.org.