High resolution dynamical mapping of social interactions with active   RFID
  In this paper we present an experimental framework to gather data on face-to-face social interactions between individuals, with a high spatial and temporal resolution. We use active Radio Frequency Identification (RFID) devices that assess contacts with one another by exchanging low-power radio packets. When individuals wear the beacons as a badge, a persistent radio contact between the RFID devices can be used as a proxy for a social interaction between individuals. We present the results of a pilot study recently performed during a conference, and a subsequent preliminary data analysis, that provides an assessment of our method and highlights its versatility and applicability in many areas concerned with human dynamics. 
Alain Barrat, Ciro Cattuto, Vittoria Colizza, Jean-Francois Pinton,   Wouter Van den Broeck, Alessandro Vespignani