What is unsupervised learning?
Unsupervised Learning (see wikipedia) is used when no historical data is available that involves past faulty behaviour and/or ageing progression. Therefore, Unsupervised Learning is mandatory to design data-based alarm system and ageing monitoring algorithms in the majority of industrial situations. This is at least true in the current state of data availability and labelling.
Typical solutions to this problem need a so called normality space to be defined. This is the space of configuration of features that characterizes the healthy behaviour of the equipment. Roughly speaking, when the features leave the normality space (in some sens), an alarm can be raised.
As it is always the case in Machine Learning (ML)-based learning, the main questions are:
- What are the features to use in the previously described process?
- What is the impact of this choice of features on the quality of the resulting alarm system in terms of coverage rate and false alarm ?
An obvious partial answer to these questions is that if the set of features being used does not intersect with the set of features impacted by a specific potential default, then this default will not fire the alarm system. Saying it differently, this fault will not be covered. Consequently, the more discriminant features one involves in the definition of the normality space, the more chance one gets to cover the multiple possible failures in the equipment.
Why is Amiral Technologies’ software solution DiagFit for unsupervised learning so powerful and innovative?
This is precisely why the Unsupervised Learning solution – the DiagFit software – of Amiral Technologies outperforms alternative solutions. Indeed, Amiral Technologies’ Automatic Feature Generation enables very rich and highly discriminant sets of features to be generated. This leaves small chances for faulty behaviours (even unseen in the learning data) to remain undetected. Moreover, the availability of such a high number of features enables the definition of voting systems that reduces the risk of false alarms as these can rapidly render the solution unacceptable by the practitioners and the maintenance operators.
Once the normality space has been built for the equipment, what happens when an alarm is raised by DiagFit (goes out of the normality space) while the equipment is operated? Amiral Technologies has developed a Feedback function in DiagFit, which allows domain experts to label alarms. This contributes to enrich a repository of alarms overtime for the equipment, and to get a dynamic normality space being more and more accurate.