Fog computing systems and methods

A fog computing system comprising a plurality of fog nodes including edge nodes at an edge or bottom level, and middle nodes at one or more middle levels intermediating between the edge nodes and a cloud node at a cloud or top level, wherein

• the cloud and middle nodes are non-bottom level nodes, the middle and edge nodes are non-top level nodes, and said non-bottom and non-top nodes form a hierarchical structure with each of the non-bottom nodes having children nodes at a next lower level, and each of the non-top nodes having a parent node at a next higher level;
• wherein
• each of the edge nodes is configured to perform the following functions:
• receiving sensor data produced by sensors, assigning a reception timestamp to each of said sensor data indicating a time of receipt to produce a corresponding series of timestamp-ordered sensor data, training a first local model through a machine learning based on said series of timestamp-ordered sensor data, and sending said series of timestamp-ordered sensor data to the parent node of the edge node;
• wherein
• each of the middle nodes is configured to perform the following functions:
• collecting a series of timestamp-ordered sensor data from the children nodes of the middle node to obtain a collected series of timestamp-ordered sensor data, training a first supra-local model through the machine learning based on the collected series of timestamp-ordered sensor data, and sending the collected series of timestamp-ordered sensor data to the parent node of the middle node.