Special issue "a Festschrift in Honor of Prof. Anthony Ephremides' 80th birthday: A journey from age of information to semantics of information"

Age of Information (AoI) is an end-to-end metric that can capture one semantic property known as the timeliness of information, which is essential in status-updating systems. Semantics of Information (SoI) captures properties of information that relate to the "goal" and "purpose" of information, which is to improve the performance of systems using the information. As a new paradigm shift toward 6G communications systems, SoI will create systems that generate, process, and transmit only a small fraction of information. Thus, they consume less energy and channel resources without sacrificing their effectiveness.