Introducing Agility in Hybrid Communication Systems and Sensors

This paper presents a new approach in dealing with hybridization issues in communication systems or sensors. The thrust is to separate the logical network (sensor) infrastructure from the physical one. Here we show how we can exploit concepts such as persistent identification which we believe is crucial to be able to connect a variety of heterogeneous devices in a network that grows, and that is robust to failures. A vital characteristic of our architecture is the ability to accommodate a variety of heterogeneous devices and subsystems. Several examples of hybridization of sensors at the physical, logical, and network levels are presented and discussed

Critical node lifetimes in random networks via the Chen-Stein method

This correspondence considers networks where nodes are connected randomly and can fail at random times. It provides scaling laws that allow to find the critical time at which isolated nodes begin to appear in the system as its size tends to infinity. Applications are in the areas of sensor and ad-hoc networks where nodes are subject to battery drainage and 'blind spots' formation becomes a primary concern. The techniques adopted are based on the Chen-Stein method of Poisson approximation, which allows to obtain elegant derivations that are shown to improve upon and simplify previous related results that appeared in the literature. Since blind spots are strongly related to full connectivity, we also obtain some scaling results about the latter. © 2006 IEEE