Date Added: May 2011
The need to monitor groups of mobile entities arises in many application contexts. Examples include the study of the social behavior of humans and wildlife, the shepherding of livestock, the care giving to people that are not self-sufficient. Human- or animal-borne wireless devices can be used to detect the joining or leaving of group members, even in infrastructureless scenarios. In this paper, the authors apply wireless sensor networks devices to this problem that has hitherto received little attention. They analyze three points of the solution space. At one extreme, group membership information is proactively and collectively maintained by each node in the group.