Abstract
The rapid adoption of Internet-of-Things (IoT) and digital twins (DTs) technologies within industrial environments has highlighted diverse critical issues related to safety and security. Sensor failure is one of the major threats compromising DTs operations. In this paper, for the first time, we address the problem of sensor fault detection, isolation and accommodation (SFDIA) in large-size networked systems. Current available machine-learning solutions are either based on shallow networks unable to capture complex features from input graph data or on deep networks with overshooting complexity in the case of large number of sensors. To overcome these challenges, we propose a new framework for sensor validation based on a deep recurrent graph convolutional architecture which jointly learns a graph structure and models spatio-temporal inter-dependencies. More specifically, the proposed two-block architecture (i) constructs the virtual sensors in the first block to refurbish anomalous (i.e. faulty) behaviour of unreliable sensors and to accommodate the isolated faulty sensors and (ii) performs the detection and isolation tasks in the second block by means of a classifier. Extensive analysis on two publicly-available datasets demonstrates the superiority of the proposed architecture over existing state-of-the-art solutions.