Information freshness is of critical importance in a variety of networked monitoring and control systems such as intelligent vehicular systems, channel state feedback, and environmental monitoring. In these types of applications, stale information can lead to incorrect decisions, unstable control loops, and even compromises in safety and security. A recent line of research has considered information freshness from a fundamental perspective under an "Age of Information" (AoI) metric first proposed in 2011. Early work in a simple single-source single-monitor setting showed the somewhat surprising result that there exists an optimal rate at which a source must generate its information to keep its status as timely as possible at the monitor. This rate differs from the rate that maximizes throughput and the rate that minimizes delivery delay. In this talk, we will provide an overview of the concept of AoI, discuss a stochastic hybrid systems (SHS) approach to analyze AoI in certain settings, present recent results on AoI using SHS analysis in a single-source single-monitor setting with a server with energy constraints, and also present recently derived results on the fundamental limits of information freshness in multi-source multi-monitor multi-hop wireless networks with explicit contention.
D. Richard Brown III is currently a Professor and the Associate Department Head in the Department of Electrical and Computer Engineering at Worcester Polytechnic Institute, where he has been a faculty member since 2000. He received a PhD in Electrical Engineering from Cornell University in 2000 and MS and BS degrees in Electrical Engineering from The University of Connecticut in 1996 and 1992, respectively. From 1992-1997, he was a design engineer at General Electric Electrical Distribution and Control in Plainville, Connecticut. From August 2007 to June 2008, he held an appointment as a Visiting Associate Professor at Princeton University. From 2016-2018, he served as a Program Director at the National Science Foundation in the Computing and Communications Foundations (CCF) division of the Directorate for Computer & Information Science & Engineering (CISE). He is also currently serving as an Associate Editor for IEEE Transactions on Wireless Communications.