On change detection for improved reliability

Change detection problem refers to the detection of abnormal regimes and incipient faults of electrical circuits, devices or equipments. The problem is coming more and more important as the requirements for high and constant quality, low maintenance and high reliability of complex electronic products are continuously increasing. Classical methods use statistical signal processing techniques, various frequency transforms and techniques based on models. In all these approaches the moment of change detection must be known as precisely as possible. This work presents preliminary results in solving change detection problem based on two methods. The first one is based on signal modeling and detects changes by observing the changes in the model´s parameters. The second one is based on Renyi entropy processing and it uses direct, simple and efficient parameter estimation methods to describe the circuit´s behavior. Both methods could serve as references for other more advanced techniques, e.g. based on frequency transforms and complex optimization criteria.