I. Introduction
Wireless Sensor Networks (WSN), core infrastructure of Internet of Things, may experience anomalies due to malfunction of either hardware or software, which cause failures in sensor nodes [1]–[3]. Such anomalies may lead a node to either shutdown, when it is related to power management, or to compromise the reliability of the transmitted data, resulting in errors on the information, which can even affect the network operation from a security point of view [4]. Therefore, network management tools must be able to detect not only shutdown conditions of sensor nodes, but also their malfunctioning.