Sensor infrastructure

A method of detecting an occurrence in a material, the method comprising:

• distributing a plurality of sensor nodes in a structure, wherein each of the sensor nodes includes an internal analog-to-digital conversion element;
• passively collecting data related to the structure from at least one of the plurality of nodes;
• analyzing the data to identify a structural occurrence in the structure by comparing the data to a baseline measurement of the structure;
• triggering an active damage detection operation in response to an identified structural occurrence to determine a location and a degree of the structural occurrence, wherein the active damage detection operation includes at least one of the plurality of nodes supplying excitation energy to the structure;
• collecting data related to the structure using at least one of the plurality of nodes during the active damage detection operation;
• passing at least one of i) the data collected at a first of the plurality of nodes, and ii) data derived from the data collected at the first of the plurality of nodes to a second node;
• combining the data from the first node with data collected at the second node;
• and
• determining a position of a structural occurrence based on the data from the first node and the data from the second node.