Findings from an empirical study of fine-grained human social contacts

An interaction based human contact study experiment has been conducted on 25 undergraduate students at USC, each carrying a wireless device (Tmote) for a week duration. Each mote transmits contact packets every 0.1 second to advertise its presence and a node receiving the packets will record the contact information. Data is processed off-line and a contact graph has been generated based on the strength of pairwise contact in order to visualize the grouping effect. All groups are identified and it has been found out that although most groups have small sizes and infrequent meetings, there exist large groups that have encountered several times in one week duration. The inter-contact and contact time distributions are found to be similar to findings from previous studies done in different settings. The inter-group contact time and group contact time distributions are also found to be power law and exponential in different time scales. Moreover, the contact arrival process is found to be self similar for data from both our experiment and the Haggle project [4].