Abstract: A network system comprising: a plurality of edge devices (10, 10?), an edge device (10) thereof comprising: at least one data source (13) configured to obtain environmental data related to an event in the edge device or its vicinity, an edge processing means (12) configured 5 to produce edge processed data comprising at least one value representative for a class selected for classifying the event, and an edge communication means (11); a plurality of fog devices (20), a fog device thereof being associated with a subset of said plurality of edge devices (10, 10) and comprising a fog communication means (21), a fog processing means (22) configured to process the edge processed data and to produce fog processed data, and a central control 10 system (30) in communication with said plurality of fog devices and configured to receive fog processed data from said plurality of fog devices.